Filed Pursuant to Rule 424(b)(5)
Registration No. 333-252793

CALCULATION OF REGISTRATION FEE

Prospectus Supplement

(To Prospectus dated February 5, 2021)

3,283,950 American Depositary Shares

I-MAB

Representing 7,553,085 Ordinary Shares

This is a public offering of American depositary shares (the “ADSs”) of I-Mab. Each ten (10) ADSs represent twenty-three (23) of our ordinary shares, par value US$0.0001 per share. We are not selling any ADSs. The selling shareholders identified in this prospectus supplement are selling 3,283,950 ADSs. We will not receive any proceeds from the sale of ADSs by the selling shareholders.

Our ADSs are listed on the Nasdaq Global Market under the symbol “IMAB.” On February 5, 2021, the closing trading price for our ADSs, as reported on the Nasdaq Global Market, was US$62.0 per ADS.

Investing in the ADSs involves risks. See “Risk Factors” beginning on page S-21 for factors you should consider before buying the ADSs.

Neither the United States Securities and Exchange Commission nor any other regulatory body has approved or disapproved of these securities, or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

PRICE US$54.0 PER ADS

Certain selling shareholders have granted the underwriters an option to purchase up to an additional 492,590 ADSs within 30 days from the date of this prospectus supplement at the offering price, less the underwriting discounts and commissions.

The underwriters expect to deliver the ADSs against payment in U.S. dollars in New York, New York on or about February 11, 2021.

The date of this prospectus supplement is February 8, 2021.

TABLE OF CONTENTS

PROSPECTUS SUPPLEMENT

PROSPECTUS

You should rely only on the information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus. We have not and the underwriters have not, authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. None of the underwriters or selling shareholders is making an offer to sell the securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus supplement, the accompanying

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prospectus and the documents incorporated by reference is accurate only as of each of their respective dates. Our business, financial condition, results of operations and prospects may have changed since those dates. Neither this prospectus supplement nor the accompanying prospectus constitutes an offer, or an invitation on our behalf or the underwriter to subscribe for and purchase, any of the ordinary shares or the ADSs and may not be used for or in connection with an offer or solicitation by anyone, in any jurisdiction in which such an offer or solicitation is not authorized or to any person to whom it is unlawful to make such an offer or solicitation.

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ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is this prospectus supplement, which describes the terms of the offering and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference in this prospectus supplement and the accompanying prospectus. The second part is the accompanying prospectus dated February 5, 2021 included in the registration statement on Form F-3 (No. 333-252793), which provides more general information.

To the extent there is a conflict between the information contained in this prospectus supplement, on the one hand, and the information contained in the accompanying prospectus or any document incorporated by reference in this prospectus supplement or the accompanying prospectus, on the other hand, you should rely on the information in this prospectus supplement.

In this prospectus supplement, unless otherwise indicated or unless the context otherwise requires:

Unless the context indicates otherwise, all information in this prospectus supplement assumes no exercise by the underwriters of their option to purchase additional ADSs.

Our reporting currency is RMB. This prospectus supplement also contains translations of certain foreign currency amounts into U.S. dollars for the convenience of the reader. Unless otherwise stated, all translations from RMB to U.S. dollars were made at a rate of RMB6.7896 to US$1.00, the exchange rate in effect as of September 30, 2020 as set forth in the H.10 statistical release of the Board of Governors of the Federal Reserve System. We make no representation that any RMB or U.S. dollar amounts referred to in this prospectus supplement could have been or could be converted into U.S. dollars or RMB, as the case may be, at any particular rate, or at all. On January 29, 2021, the exchange rate as set forth in the H.10 statistical release of the Board of Governors of the Federal Reserve System was RMB6.4282 to US$1.00.

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SPECIAL NOTES REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement, the accompanying prospectus and the information incorporated by reference herein and therein may contain forward-looking statements that involve risks and uncertainties. All statements other than statements of historical facts are forward-looking statements. These statements are made under the “safe harbor” provisions of the U.S. Private Securities Litigation Reform Act of 1995. You can identify these forward-looking statements by words or phrases such as “may,” “will,” “expect,” “anticipate,” “aim,” “estimate,” “intend,” “plan,” “believe,” “likely to,” “potential,” “continue” or other similar expressions. We have based these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our financial condition, results of operations, business strategy and financial needs. These forward-looking statements include, but are not limited to, statements about:

The forward-looking statements included in this prospectus supplement, the accompanying prospectus and the information incorporated by reference herein and therein involve various risks and uncertainties. Although we believe that our expectations expressed in these forward-looking statements are reasonable, our expectations may later be found to be incorrect. Our actual results could be materially different from our expectations. Other sections of this prospectus supplement include additional factors that could adversely impact our business and financial performance. Moreover, we operate in an evolving environment. New risk factors and uncertainties emerge from time to time and it is not possible for our management to predict all risk factors and uncertainties, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements. You should read thoroughly this prospectus supplement and the documents that we refer to with the understanding that our actual future results may be materially different from, or worse than, what we expect. We qualify all of our forward-looking statements by these cautionary statements.

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This prospectus supplement contains certain data and information that we obtained from various government and private publications. Statistical data in these publications also include projections based on a number of assumptions. The electric vehicles industry may not grow at the rate projected by market data, or at all. Failure of this market to grow at the projected rate may have a material and adverse effect on our business and the market price of our ADSs. In addition, the rapidly evolving nature of the electric vehicles industry results in significant uncertainties for any projections or estimates relating to the growth prospects or future condition of our market. Furthermore, if any one or more of the assumptions underlying the market data are later found to be incorrect, actual results may differ from the projections based on these assumptions.

We would like to caution you not to place undue reliance on the forward-looking statements and you should read these statements in conjunction with the risk factors disclosed in the documents incorporated by reference herein for a more complete discussion of the risks of an investment in our securities and other risks outlined in our other filings with the SEC. The forward-looking statements included in this prospectus supplement or incorporated by reference into this prospectus supplement are made only as of the date of this prospectus supplement or the date of the incorporated document, and we do not undertake any obligation to update the forward-looking statements except as required under applicable law.

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RISK FACTORS

An investment in the ADSs involves significant risks. You should carefully consider all of the information in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference, including the risks and uncertainties described below, before making an investment in the ADSs. Any of the following risks could have a material adverse effect on our business, financial condition and results of operations. In any such case, the market price of our ADSs could decline, and you may lose all or part of your investment.

Risks Related to Our Financial Position and Need for Additional Capital

We have a limited operating history, which may make it difficult to evaluate our current business and predict our future performance.

We are a clinical stage biopharmaceutical company with a limited operating history. Our operations to date have focused on organizing and staffing our operations, business planning, raising capital, establishing our intellectual property portfolio and conducting pre-clinical and clinical trials of our drug candidates. We have not yet demonstrated an ability to successfully manufacture, obtain marketing approvals for or commercialize our drug candidates. We have no products approved for commercial sale and have not generated any revenue from product sales. Consequently, any predictions about our future success or viability may not be as accurate as they could be if we had a longer operating history.

We are focused on the discovery and development of innovative drugs for the treatment of various immuno-oncological and immuno-inflammatory diseases. Our limited operating history, particularly in light of the rapidly evolving drug research and development industry in which we operate and the changing regulatory and market environments we encounter, may make it difficult to evaluate our prospects for future performance. As a result, any assessment of our future performance or viability is subject to significant uncertainty. We will encounter risks and difficulties frequently experienced by early-stage companies in rapidly evolving fields as we seek to transition to a company capable of supporting commercial activities. If we do not address these risks and difficulties successfully, our business will suffer.

We have incurred net losses in each period since our inception and anticipate that we will continue to incur net losses for the foreseeable future and may never achieve or maintain profitability.

Investment in the development of biopharmaceutical products is highly speculative as it entails substantial upfront capital expenditures and significant risks that a drug candidate may fail to demonstrate efficacy and/or safety to gain regulatory or marketing approvals or become commercially viable. To date, we have financed our activities primarily through private placements. While we have generated revenue from licensing and collaboration deals, we have not generated any revenue from commercial product sales to date, and we continue to incur significant research and development expenses and other expenses related to our ongoing operations. As a result, we are not profitable and have incurred net losses in each period since our inception. In 2017, 2018, 2019 and the nine months ended September 30, 2020, our net losses were RMB298.2 million, RMB402.8 million, RMB1,452.0 million (US$213.8 million) and RMB570.6 million (US$84.0 million), respectively. Substantially all of our net losses have resulted from costs incurred in connection with our research and development programs and from general and administrative costs associated with our operations.

We expect to continue to incur net losses in the foreseeable future, and that these net losses will increase as we carry out certain activities relating to our development, including, but not limited to, the following:

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Typically, it takes many years to develop one new drug from the time it is discovered to when it becomes available for treating patients. During the process, we may encounter unforeseen expenses, difficulties, complications, delays and other unknown factors that may adversely affect our business. The size of our future net losses will depend partially on the rate of the future growth of our expenses, our ability to generate revenues and the timing and amount of milestone payments and other payments that we receive from or pay to third parties. If any of our drug candidates fails during clinical trials or does not gain regulatory approval, or, even if approved, fails to achieve market acceptance, our business may not become profitable. Even if we achieve profitability in the future, we may not be able to sustain profitability in subsequent periods thereafter. Our prior losses and expected future losses have had, and will continue to have, an adverse effect on our working capital and shareholders’ equity.

We recorded net cash outflow from operating activities since our inception. We may need to obtain additional financing to fund our operations. If we are unable to obtain such financing, we may be unable to complete the development and commercialization of our major drug candidates.

Since our inception, our operations have consumed substantial amounts of cash. We had raised over US$400 million in pre-IPO financing in the past three years and received total net proceeds of approximately US$105.3 million from our initial public offering. We spent RMB252.2 million, RMB280.7 million, RMB868.0 million (US$127.8 million) and RMB582.6 million (US$85.8 million) in net cash to finance our operations in 2017, 2018, 2019 and the nine months ended September 30, 2020, respectively.

We expect our expenses to increase significantly in connection with our ongoing activities, particularly as we advance the clinical development of our clinical-stage drug candidates, continue the research and development of our pre-clinical stage drug candidates and initiate additional clinical trials of, and seek regulatory approval for, these and other future drug candidates.

In addition, if we obtain regulatory approvals for any of our drug candidates, we expect to incur significant commercialization expenses relating to product manufacturing, marketing, sales and distribution and post-approval commitments to continue monitoring the efficacy and safety data of our future products on the market. In particular, costs that may be required for the manufacture of any drug candidate that has received regulatory approval may be substantial as we may need to modify or increase our production capacity in the future at manufacturing facilities. We may also incur expenses as we create additional infrastructure to support our operations as a public company. Accordingly, we will need to obtain substantial additional funding in connection

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with our continuing operations through public or private equity offerings, debt financing, collaborations or licensing arrangements or other sources. If we are unable to raise capital when needed or on acceptable terms, we could be forced to delay, limit, reduce or terminate our research and development programs or any future commercialization efforts.

The recent COVID-19 outbreak has brought uncertainties and interruptions to global economy and caused significant volatility across the financial markets, which had a cooling effect on the financing and investing activities in general. We believe that our current cash and cash equivalents, together with our cash generated from operating activities, financing activities, our initial public offering and private placement, will be sufficient to meet our present anticipated working capital requirements and capital expenditures. However, if the impact of the COVID-19 and volatility in the financial markets continue, our financing activities in future to raise additional capital may be materially and adversely affected, which may in turn have an adverse effect on our ability to meet our working capital requirement and our liquidity. For other risks related to the COVID-19, see “—Our business and results of operations could be adversely affected by public health crisis (including the COVID-19 global pandemic) and natural catastrophes or other disasters outside of our control in the locations in which we, our suppliers, CROs, CMOs and other contractors operate.”

Raising additional capital may cause dilution to the interests to the holders of our ADSs and our shareholders, restrict our operations or require us to relinquish rights to our technologies or drug candidates.

We may seek additional funding through a combination of equity offerings, debt financings, collaborations, licensing arrangements, strategic alliances or partnerships and government grants or subsidies. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms may include liquidation or other preferences that adversely affect your rights as a holder of our ADSs. The incurrence of additional indebtedness or the issuance of certain equity securities could give rise to increased fixed payment obligations and also result in certain additional restrictive covenants, such as limitations on our ability to incur additional debt or issue additional equity, limitations on our ability to acquire or license intellectual property rights and other operating restrictions that could adversely impact our ability to conduct our business. In addition, the issuance of additional equity securities, or the possibility of such issuance, may cause the market price of our ADSs to decline.

In the event we enter into collaborations or licensing arrangements in order to raise capital, we may be required to accept unfavorable terms, including relinquishing or licensing to a third party our rights to technologies or drug candidates on unfavorable terms, which we would have otherwise sought to develop or commercialize on our own or reserve for future potential arrangements when we are more likely to achieve more favorable terms.

Risks Related to Clinical Development of Our Drug Candidates

Clinical development involves a lengthy and expensive process with an uncertain outcome, and results of earlier studies and trials may not be predictive of future trial results.

Clinical testing is expensive and can take many years to complete, and its outcome is inherently uncertain. While our exclusive focus is to develop drug candidates with potential to become novel or highly differentiated drugs in China and globally, we cannot guarantee that we are able to achieve this for any of our drug candidates. Failure can occur at any time during the clinical development process. The results of pre-clinical studies and early clinical trials of our drug candidates may not be predictive of the results of later-stage clinical trials. Drug candidates during later stages of clinical trials may fail to show the desired results in safety and efficacy despite having progressed through pre-clinical studies and initial clinical trials and despite the level of scientific rigor in the study, design and adequacy of execution. In some instances, there can be significant variability in safety and/or efficacy results among different trials of the same drug candidate due to numerous factors, including, but not limited to, differences in individual patient conditions, including genetic differences, and other compounding factors, such as other medications or pre-existing medical conditions.

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In the case of any trials we conduct, results may differ from earlier trials due to the larger number of clinical trial sites and additional countries and languages involved in such trials. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to a lack of efficacy or adverse safety profiles, notwithstanding promising results in earlier trials. We cannot guarantee that our future clinical trial results will be favorable based on currently available clinical and pre-clinical data.

We depend substantially on the success of our drug candidates, all of which are in pre-clinical or clinical development, and our ability to identify additional drug candidates. If we are unable to successfully identify new drug candidates, complete clinical development, obtain regulatory approval and commercialize our drug candidates, or experience significant delays in doing so, our business will be materially harmed.

Our business will depend on the successful development, regulatory approval and commercialization of our drug candidates for the treatment of patients with our targeted indications, all of which are still in pre-clinical or clinical development, and other new drug candidates that we may identify and develop. As of the date of this prospectus supplement, we have obtained IND approvals from the NMPA for seven of our drug candidates, felzartamab, olamkicept, efineptakin, lemzoparlimab, uliledlimab, plonmarlimab and eftansomatropin. In addition, we have obtained IND approvals from the FDA for four of our drug candidates, lemzoparlimab, uliledlimab, plonmarlimab and TJ210; from the Taiwan Food and Drug Administration (the “TFDA”) for two of our drug candidates, felzartamab and olamkicept; and from the Korea Ministry of Food and Drug Safety (the “MFDS”) for olamkicept. However, we cannot guarantee that we are able to obtain regulatory approvals for our other existing drug candidates in a timely manner, or at all. In addition, none of our drug candidates has been approved for marketing in China or any other jurisdiction. Each of our drug candidates will require additional pre-clinical and/or clinical development, regulatory approvals in multiple jurisdictions, development of manufacturing supply and capacity, substantial investment and significant marketing efforts before we generate any revenue from product sales.

The success of our drug candidates will depend on several factors, including but not limited to the successful completion of pre-clinical and/or clinical trials or studies, receipt of regulatory approvals from applicable regulatory authorities for planned clinical trials, future clinical trials or drug registrations, establishing adequate manufacturing capabilities and capacities, commercialization of our existing drug candidates, hiring sufficient technical experts to oversee all development and regulatory activities and license renewal and meeting of the safety requirements.

If we do not achieve one or more of these in a timely manner or at all, we could experience significant delays in our ability to obtain approval for our drug candidates, which would materially harm our business and we may not be able to generate sufficient revenues and cash flows to continue our operations. As a result, our financial condition, results of operations and prospects will be materially and adversely harmed.

We may not be able to identify, discover or in-license new drug candidates, and may allocate our limited resources to pursue a particular drug candidate or indication and fail to capitalize on drug candidates or indications that may later prove to be more profitable, or for which there is a greater likelihood of success.

Although a substantial amount of our effort will focus on the continued clinical testing, potential approval, and commercialization of our existing drug candidates, the success of our business depends in part upon our ability to identify, license, discover, develop, or commercialize additional drug candidates. Research programs to identify new drug candidates require substantial technical, financial, and human resources. We may focus our efforts and resources on potential programs or drug candidates that ultimately prove to be unsuccessful. Our research programs or licensing efforts may fail to identify, discover or in-license new drug candidates for clinical development and commercialization for a number of reasons, including, without limitation, the following:

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Because we have limited financial and managerial resources, we focus on research programs and drug candidates for specific indications. As a result, we may forgo or delay pursuit of opportunities with other drug candidates or for other indications that later may prove to have greater commercial potential or a greater likelihood of success. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities.

Accordingly, there can be no assurance that we will ever be able to identify additional therapeutic opportunities for our drug candidates or to develop suitable potential drug candidates through internal research programs, which could materially adversely affect our future growth and prospects.

If we encounter delays or difficulties enrolling patients in our clinical trials, our clinical development progress could be delayed or otherwise adversely affected.

We may not be able to initiate or continue clinical trials for our drug candidates if we are unable to locate and enroll a sufficient number of eligible patients to participate in these trials as required by the NMPA, the FDA, or similar regulatory authorities, or if there are delays in the enrollment of eligible patients as a result of the competitive clinical enrollment environment. The inability to enroll a sufficient number of patients who meet the applicable criteria for our clinical trials would result in significant delays. As of the date of this prospectus supplement, we have initiated clinical trials for olamkicept in South Korea and Greater China, for efineptakin in China, for felzartamab in Greater China, for lemzoparlimab, plonmarlimab and uliledlimab in China and the United States. In addition, we expect to initiate clinical trials for TJ210 by early 2021 in the United States.

In addition, some of our competitors have ongoing clinical trials for drug candidates that treat the same indications as our drug candidates, and patients who would otherwise be eligible for our clinical trials may instead enroll in the clinical trials of our competitors’ drug candidates, which may further delay our clinical trial enrollments.

Patient enrollment for our clinical trials may be affected by other factors, including but not limited to the following:

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Even if we are able to enroll a sufficient number of patients in our clinical trials, delays in patient enrollment may result in increased costs or may affect the timing or outcome of the planned clinical trials, which could prevent completion of these trials and adversely affect our ability to advance the development of our drug candidates.

If clinical trials of our drug candidates fail to demonstrate safety and efficacy to the satisfaction of regulatory authorities or do not otherwise produce positive results, we may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of our drug candidates.

Before obtaining regulatory approval for the sale of our drug candidates, we must conduct extensive clinical trials to demonstrate the safety and efficacy of our drug candidates in humans. We may experience numerous unexpected events during, or as a result of, clinical trials that could delay or prevent our ability to receive regulatory approval or commercialize our drug candidates, including, without limitation:

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If we are required to conduct additional clinical trials or other testing of our drug candidates beyond those that we currently plan, if we are unable to successfully complete clinical trials of our drug candidates or other testing, if the results of these trials or tests are not positive or are only modestly positive or if they raise safety concerns, we may (i) be delayed in obtaining regulatory approval for our drug candidates; (ii) obtain approval for indications that are not as broad as intended; (iii) not obtain regulatory approval at all; (iv) have the drug removed from the market after obtaining regulatory approval; (v) be subject to additional post-marketing testing requirements; (vi) be subject to restrictions on how the drug is distributed or used; or (vii) be unable to obtain reimbursement for use of the drug.

Significant clinical trial delays may also increase our development costs and could shorten any periods during which we have the exclusive right to commercialize our drug candidates or allow our competitors to bring drugs to market before we do. This could impair our ability to commercialize our drug candidates and may harm our business and results of operations.

Risks Related to Obtaining Regulatory Approval for Our Drug Candidates

All material aspects of the research, development and commercialization of pharmaceutical products are heavily regulated.

All jurisdictions in which we intend to conduct our pharmaceutical-industry activities regulate these activities in great depth and detail. We intend to focus our activities in the major markets of China and the United States. These jurisdictions strictly regulate the pharmaceutical industry, and in doing so they employ broadly similar regulatory strategies, including regulation of product development and approval, manufacturing, and marketing, sales and distribution of products. However, there are differences in the regulatory regimes that make for a more complex and costly regulatory compliance burden for a company like us that plans to operate in these regions.

The process of obtaining regulatory approvals and compliance with appropriate laws and regulations requires the expenditure of substantial time and financial resources. Failure to comply with the applicable requirements at any time during the product development process and approval process, or after approval, may subject an applicant to administrative or judicial sanctions. These sanctions could include: refusal to approve pending applications; withdrawal of an approval; license revocation; clinical hold; voluntary or mandatory product recalls; product seizures; total or partial suspension of production or distribution; injunctions; fines; refusals of government contracts; providing restitution; undergoing disgorgement; or other civil or criminal penalties. Failure to comply with these regulations could have a material adverse effect on our business.

The regulatory approval processes of the NMPA, the FDA and other comparable regulatory authorities are time-consuming and may evolve over time, and if we are ultimately unable to obtain regulatory approval for our drug candidates, our business will be substantially harmed.

The time required to obtain the approval of the NMPA, the FDA and other comparable regulatory authorities is inherently uncertain and depends on numerous factors, including the substantial discretion of the regulatory authorities. Generally, such approvals take many years to obtain following the commencement of pre-clinical studies and clinical trials, although they are typically provided within 12 to 18 months after clinical trials are completed. In addition, approval policies, regulations or the type and amount of clinical data necessary to gain approval may change during the course of a drug candidate’s clinical development and may vary among jurisdictions. As of the date of this prospectus supplement, we have obtained IND approvals from the NMPA for seven of our drug candidates, felzartamab, olamkicept, efineptakin, lemzoparlimab, uliledlimab, plonmarlimab and eftansomatropin. In addition, we have obtained IND approvals from the FDA for four of our drug candidates, lemzoparlimab, uliledlimab, plonmarlimab and TJ210; from the TFDA for two of our drug candidates, felzartamab and olamkicept; and from the MFDS for olamkicept. However, we cannot guarantee that we are able to obtain regulatory approvals for our other existing drug candidates or any drug candidates we may discover, in-license or acquire and seek to develop in the future.

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Our drug candidates could fail to receive the regulatory approval of the NMPA, the FDA or a comparable regulatory authority for many reasons, including, without limitation:

The NMPA, the FDA or a comparable regulatory authority may require more information, including additional pre-clinical or clinical data, to support approval, which may delay or prevent approval and our commercialization plans. Even if we were to obtain approval, regulatory authorities may approve any of our drug candidates for fewer or more limited indications than we request, grant approval contingent on the performance of costly post-marketing clinical trials, or approve a drug candidate with an indication that is not desirable for the successful commercialization of that drug candidate. Any of the foregoing scenarios could materially harm the commercial prospects of our drug candidates.

The absence of patent linkage, patent term extension and data and market exclusivity for NMPA-approved pharmaceutical products could increase the risk of early generic competition with our products in China.

In the United States, the Federal Food, Drug and Cosmetic Act, as amended by the law generally referred to as “Hatch-Waxman,” provides the opportunity for patent-term restoration, meaning a patent term extension of up to five years to reflect patent term lost during certain portions of product development and the FDA regulatory review process. Hatch-Waxman also has a process for patent linkage, pursuant to which the FDA will stay approval of certain follow-on applications during the pendency of litigation between the follow-on applicant and the patent holder or licensee, generally for a period of 30 months. Finally, Hatch-Waxman provides for statutory exclusivities that can prevent submission or approval of certain follow-on marketing applications. For example,

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federal law provides a five-year period of exclusivity within the United States to the first applicant to obtain approval of a new chemical entity and three years of exclusivity protecting certain innovations to previously approved active ingredients where the applicant was required to conduct new clinical investigations to obtain approval for the modification. Similarly, the United States Orphan Drug Act provides seven years of market exclusivity for certain drugs to treat rare diseases, where the FDA designates the drug candidate as an orphan drug and the drug is approved for the designated orphan indication. These provisions, designed to promote innovation, can prevent competing products from entering the market for a certain period of time after the FDA grants marketing approval for the innovative product.

Depending upon the timing, duration and specifics of any FDA marketing approval process for any drug candidates we may develop, one or more of our U.S. patents, if issued, may be eligible for limited patent term extension under Hatch-Waxman. Hatch-Waxman permits a patent extension term of up to five years as compensation for patent term lost during clinical trials and the FDA regulatory review process. A patent term extension cannot extend the remaining term of a patent beyond a total of 14 years from the date of drug approval, only one patent may be extended and only those claims covering the approved drug, a method for using it, or a method for manufacturing it may be extended. However, we may not be granted an extension because of, for example, failing to exercise due diligence during the testing phase or regulatory review process, failing to apply within applicable deadlines, failing to apply prior to expiration of relevant patents, or otherwise failing to satisfy applicable requirements. Furthermore, the applicable time period or the scope of patent protection afforded could be less than we request.

In China, however, there is no currently effective law or regulation providing for patent term extension, patent linkage, or data exclusivity (referred to as regulatory data protection). Therefore, a lower-cost generic drug can emerge onto the market much more quickly. Chinese regulators have set forth a framework for integrating patent linkage and data exclusivity into the Chinese regulatory regime, as well as for establishing a pilot program for patent term extension. To be implemented, this framework will require adoption of regulations. To date, no regulations have been issued. These factors result in weaker protection for us against generic competition in China than could be available to us in the United States. For instance, the patents we have in China are not yet eligible to be extended for patent term lost during clinical trials and the regulatory review process. If we are unable to obtain patent term extension or the term of any such extension is less than we request, our competitors may obtain approval of competing products following our patent expiration, and our business, financial condition, results of operations, and prospects could be materially harmed.

Our drug candidates may cause undesirable adverse events or have other properties that could delay or prevent their regulatory approval, limit the commercial profile of an approved label, or result in significant negative consequences following regulatory approval.

Undesirable adverse events caused by our drug candidates could cause us or regulatory authorities to interrupt, delay or halt clinical trials and may result in a more restrictive label, a delay or denial of regulatory approval by the NMPA, the FDA or other comparable regulatory authorities, or a significant change in our clinical protocol or even our development plan. In particular, as is the case with drugs treating cancers and auto-immune diseases, it is likely that there may be side effects, such as nausea, fatigue and infusion-related reactions, associated with the use of certain of our drug candidates. Results of our trials could reveal a high and unacceptable severity or prevalence of certain adverse events. In such an event, our trials could be suspended or terminated and the NMPA, the FDA or other comparable regulatory authorities could order us to cease further development of, or deny approval of, our drug candidates for any or all targeted indications. Adverse events related to our drug candidates may affect patient recruitment or the ability of enrolled subjects to complete the trial, and could result in potential liability claims. Any of these occurrences may significantly harm our reputation, business, financial condition and prospects.

Additionally, if we or others identify undesirable side effects caused by those of our existing drug candidates that have received regulatory approval, or our other drug candidates after having received regulatory

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approval, this may lead to potentially significant negative consequences which include, but are not limited to, the following:

Any of these events could prevent us from achieving or maintaining market acceptance of any particular drug candidate that is approved and could significantly harm our business, results of operations and prospects.

Further, combination therapy, such as using our wholly-owned drug candidates as well as third-party agents, may involve unique adverse events that could be exacerbated compared with adverse events from monotherapies. Results of our trials could reveal a high and unacceptable severity or prevalence of adverse events. These types of adverse events could be caused by our drug candidates and could cause us or regulatory authorities to interrupt, delay or halt clinical trials and may result in a more restrictive indication or the delay or denial of regulatory approval by the NMPA, the FDA or other comparable regulatory authority.

If we are unable to obtain the NMPA approval for our drug candidates to be eligible for an expedited registration pathway as innovative drug candidates, the time and cost we incur to obtain regulatory approvals may increase.

The NMPA has mechanisms in place for expedited review and approval for drug candidates that are innovative drug applications, provided such drug or drug candidate has a new and clearly defined structure, pharmacological property and apparent clinical value and has not been marketed anywhere in the world. However, there is no assurance that an innovative drug designation will be granted by the NMPA for any of our drug candidates. Moreover, an innovative drug designation, which is typically granted only towards the end of a drug’s developmental stage, does not increase the likelihood that our drug candidates will receive regulatory approval on a fast-track basis, or at all.

Further, there have been recent regulatory initiatives in China in relation to clinical trial approvals, the evaluation and approval of certain drugs and medical devices and the simplification and acceleration of the clinical trial process.

As a result, the regulatory process in China is evolving and subject to change. Any future policies, or changes to current polices might require us to change our planned clinical study design or otherwise spend additional resources and effort to obtain approval of our drug candidates. In addition, policy changes may contain significant limitations related to use restrictions for certain age groups, warnings, precautions or contraindications, or may be subject to burdensome post-approval study or risk management requirements. If we

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are unable to obtain regulatory approval for our drug candidates in the PRC, or any approval contains significant limitations, we may not be able to obtain sufficient funding or generate sufficient revenue to continue the development of our drug candidates or any other drug candidate that we may in-license, acquire or develop in the future.

Even if we receive regulatory approval for our drug candidates, we will be subject to ongoing regulatory obligations and continued regulatory review, which may result in significant additional expenses and we may be subject to penalties if we fail to comply with regulatory requirements or experience unanticipated problems with our drug candidates.

If the NMPA, the FDA or a comparable regulatory authority approves any of our drug candidates, the manufacturing processes, labeling, packaging, distribution, adverse event reporting, storage, advertising, promotion and recordkeeping for the drug will be subject to extensive and ongoing regulatory requirements on pharmacovigilance. These requirements include submissions of safety and other post-marketing information and reports, registration, random quality control testing, adherence to any chemistry, manufacturing, and controls (“CMC”), variations, continued compliance with current cGMPs, and GCPs and potential post-approval studies for the purposes of license renewal.

Any regulatory approvals that we receive for our drug candidates may also be subject to limitations on the approved indicated uses for which the drug may be marketed or to the conditions of approval, or contain requirements for potentially costly post-marketing studies, including Phase 4 studies for the surveillance and monitoring of the safety and efficacy of the drug.

In addition, once a drug is approved by the NMPA, the FDA or a comparable regulatory authority for marketing, it is possible that there could be a subsequent discovery of previously unknown problems with the drug, including problems with third-party manufacturers or manufacturing processes, or failure to comply with regulatory requirements. If any of the foregoing occurs with respect to our drug products, it may result in, among other things:

Any government investigation of alleged violations of law could require us to expend significant time and resources and could generate negative publicity. Moreover, regulatory policies may change or additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our drug candidates. If we are not able to maintain regulatory compliance, we may lose the regulatory approvals that we have already obtained and may not achieve or sustain profitability, which in turn could significantly harm our business, financial condition and prospects.

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Illegal and/or parallel imports and counterfeit pharmaceutical products may reduce demand for our future approved drug candidates and could have a negative impact on our reputation and business.

The illegal importation of competing products from countries where government price controls or other market dynamics result in lower prices may adversely affect the demand for our future approved drug candidates and, in turn, may adversely affect our sales and profitability in China and other countries where we commercialize our products. Unapproved foreign imports of prescription drugs are illegal under the current laws of China. However, illegal imports may continue to occur or even increase as the ability of patients and other customers to obtain these lower priced imports continues to grow. Furthermore, cross-border imports from lower-priced markets (which are known as parallel imports) into higher-priced markets could harm sales of our future drug products and exert commercial pressure on pricing within one or more markets. In addition, competent government authorities may expand consumers’ ability to import lower priced versions of our future approved products or competing products from outside China or other countries where we operate. Any future legislation or regulations that increase consumer access to lower priced medicines from outside China or other countries where we operate could have a material adverse effect on our business.

Certain products distributed or sold in the pharmaceutical market may be manufactured without proper licenses or approvals, or be fraudulently mislabeled with respect to their content or manufacturers. These products are generally referred to as counterfeit pharmaceutical products. The counterfeit pharmaceutical product control and enforcement system, particularly in developing markets such as China, may be inadequate to discourage or eliminate the manufacturing and sale of counterfeit pharmaceutical products imitating our products. Since counterfeit pharmaceutical products in many cases have very similar appearances compared with the authentic pharmaceutical products but are generally sold at lower prices, counterfeits of our products could quickly erode the demand for our future approved drug candidates.

In addition, counterfeit pharmaceutical products are not expected to meet our or our collaborators’ rigorous manufacturing and testing standards. A patient who receives a counterfeit pharmaceutical product may be at risk for a number of dangerous health consequences. Our reputation and business could suffer harm as a result of counterfeit pharmaceutical products sold under our or our collaborators’ brand name(s). In addition, thefts of inventory at warehouses, plants or while in-transit, which are not properly stored and which are sold through unauthorized channels, could adversely impact patient safety, our reputation and our business.

Risks Related to Commercialization of Our Drug Candidates

Our drug candidates may fail to achieve the degree of market acceptance by physicians, patients, third-party payors and others in the medical community necessary for commercial success.

Even if our drug candidates receive regulatory approval, they may nonetheless fail to gain sufficient market acceptance by physicians and patients and others in the medical community. Physicians and patients may prefer other drugs or drug candidates to ours. If our drug candidates do not achieve an adequate level of acceptance, we may not generate significant revenue from sales of our drugs or drug candidates and may not become profitable.

The degree of market acceptance of our drug candidates, if and only when they are approved for commercial sale, will depend on a number of factors, including, but not limited to:

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If our drug candidates are approved but fail to achieve market acceptance among physicians, patients, hospitals or others in the medical community, we will not be able to generate significant revenue or become profitable. Even if our drugs achieve market acceptance, we may not be able to maintain such market acceptance over time if new products or technologies are introduced which are more favorably received than our drugs, are more cost effective or render our drugs obsolete.

We face intense competition and rapid technological change and the possibility that our competitors may develop therapies that are similar, more advanced, or more effective than ours, which may adversely affect our financial condition and our ability to successfully commercialize our drug candidates.

The biotechnology and pharmaceutical industries are intensely competitive and subject to rapid and significant technological change. While our exclusive focus is to develop drug candidates with potential to become novel or highly differentiated drugs, we continue to face competition with respect to our current drug candidates, and will face competition with respect to any drug candidates that we may seek to develop or commercialize in the future. Our competitors include major pharmaceutical companies, specialty pharmaceutical companies and biotechnology companies worldwide. We are developing our drug candidates for the treatment of cancer in competition with a number of large biopharmaceutical companies that currently market and sell drugs or are pursuing the development of drugs also for the treatment of cancer. Some of these competitive drugs and therapies are based on scientific approaches that are the same as or similar to our approach, and others are based on entirely different approaches. For details, see “Business—Our Drug Pipeline.” Potential competitors further include academic institutions, government agencies and other public and private research organizations that conduct research, seek patent protection and establish collaborative arrangements for research, development, manufacturing and commercialization.

Many of our competitors have substantially greater financial, technical, and other resources, such as larger research and development staff and experienced marketing and manufacturing organizations. Additional mergers and acquisitions in the biotechnology and pharmaceutical industries may result in even more resources being concentrated in our competitors. As a result, these companies may obtain regulatory approval from the NMPA, the FDA or other comparable regulatory authorities more rapidly than we are able to and may be more effective in selling and marketing their products as well. For example, the NMPA has recently accelerated market approval

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of drugs for diseases with high unmet medical need. In particular, the NMPA may review and approve drugs that have gained regulatory market approval in the United States, the European Union or Japan in the recent ten years without requiring further clinical trials in China. This may lead to potential increased competition from drugs which have already obtained approval in other jurisdictions.

Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large, established companies. Competition may increase further as a result of advances in the commercial applicability of technologies and greater availability of capital for investment in these industries. Our competitors may succeed in developing, acquiring, or licensing on an exclusive basis, products that are more effective or less costly than any drug candidate that we may develop, or achieve earlier patent protection, regulatory approval, product commercialization, and market penetration than we do. Additionally, technologies developed by our competitors may render our potential drug candidates uneconomical or obsolete, and we may not be successful in marketing our drug candidates against competitors.

The manufacture of biopharmaceutical products is a complex process which requires significant expertise and capital investment, and if we encounter problems in establishing our manufacturing capabilities or manufacturing our future products, our business could suffer.

We have limited experience in managing the manufacturing process. The manufacture of biopharmaceutical products is a complex process, in part due to strict regulatory requirements. As of the date of this prospectus supplement, we have no existing manufacturing infrastructure or capabilities. We intend to build a comprehensive biologics manufacturing facility in Hangzhou, China (the “Hangzhou Facility”) as part of our strategic plan to become a fully integrated biopharma company. We have taken concrete steps to execute this plan. These steps include detailed operational planning for the facility, actions taken to secure an appropriate site, and negotiations with external financing providers. The Hangzhou Facility targets to have a pilot capacity of 2 production lines (1 line configured with 2 x 2,000L and another line with 1 x 2,000L) by the end of 2021 and commercially progressive capacity up to 8 x 4,000L to begin operation by the end of 2023. Construction is expected to commence in April 2021 and ready for use by the end of 2023. However, the investment for building this new biologics manufacturing facility that is compliant with cGMP regulations will be a significant upfront cost for us. In turn, this could materially harm our commercialization plans.

In addition, problems may arise during the manufacturing process for a variety of reasons, including equipment malfunction, failure to follow specific protocols and procedures, problems with raw materials, delays related to the construction of new facilities or expansion of any future manufacturing facilities, including changes in manufacturing production sites and limits to manufacturing capacity due to regulatory requirements, changes in the types of products produced, increases in the prices of raw materials, physical limitations that could inhibit continuous supply, man-made or natural disasters and environmental factors. If problems arise during the production of a batch of future products, that batch of future products may have to be discarded and we may experience product shortages or incur added expenses. This could, among other things, lead to increased costs, lost revenue, damage to customer relationships, time and expense spent investigating the cause and, depending on the cause, similar losses with respect to other batches or products. If problems are not discovered before such product is released to the market, recall and product liability costs may also be incurred.

We have no experience in launching and marketing drug candidates. We may not be able to effectively build and manage our sales network, or benefit from third-party collaborators’ sales network.

We currently have no sales, marketing or commercial product distribution capabilities and have no experience in marketing drugs. We intend to develop an in-house marketing organization and sales force, which will require significant capital expenditures, management resources and time. We will have to compete with other biopharmaceutical companies to recruit, hire, train and retain marketing and sales personnel.

If we are unable or decide not to establish internal sales, marketing and commercial distribution capabilities for any or all of the drugs we develop, we will likely pursue collaborative arrangements regarding the sales and

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marketing of our drugs. However, there can be no assurance that we will be able to establish or maintain such collaborative arrangements, or, if we are able to do so, that they will have effective sales forces. Any revenue we receive will depend on the efforts of such third parties, which may not be successful. We may have little or no control over the marketing and sales efforts of such third parties, and our revenue from product sales may be lower than if we had commercialized our drug candidates ourselves. We will also face competition in our search for third parties to assist us with the sales and marketing efforts of our drug candidates.

There can be no assurance that we will be able to develop in-house sales and commercial distribution capabilities or establish or maintain relationships with third-party collaborators to successfully commercialize any product, and as a result, we may not be able to generate product sales revenue.

Even if we are able to commercialize any approved drug candidates, reimbursement may be limited or unavailable in certain market segments for our drug candidates, and we may be subject to unfavorable pricing regulations, which could harm our business.

The regulations that govern regulatory approvals, pricing and reimbursement for new therapeutic products vary widely from country to country. Some countries require approval of the sale price of a drug before it can be marketed. In many countries, the pricing review period begins after marketing or licensing approval is granted. In some non-U.S. markets, prescription pharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. As a result, we might obtain regulatory approval for a drug in a particular country, but then be subject to price regulations that delay our commercial launch of the drug and negatively impact the revenues we are able to generate from the sale of the drug in that country. Adverse pricing limitations may hinder our ability to recoup our investment in one or more drug candidates, even if our drug candidates obtain regulatory approval. For example, according to a statement, Opinions on Reforming the Review and Approval Process for Pharmaceutical Products and Medical Devices, issued by the PRC State Council in August 2015, the enterprises applying for new drug approval will be required to undertake that the selling price of new drug on PRC mainland market shall not be higher than the comparable market prices of the product in its country of origin or PRC’s neighboring markets, as applicable.

Our ability to commercialize any drugs successfully also will depend in part on the extent to which reimbursement for these drugs and related treatments will be available from government health administration authorities, private health insurers and other organizations. Government authorities and third-party payors, such as private health insurers and health maintenance organizations, decide which medications they will pay for and establish reimbursement levels. A primary trend in the global healthcare industry is cost containment. Government authorities and these third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications. Increasingly, third-party payors are requiring that companies provide them with predetermined discounts from list prices and are challenging the prices charged for medical products. We cannot be sure that reimbursement will be available for any drug that we commercialize and, if reimbursement is available, what the level of reimbursement will be. Reimbursement may impact the demand for, or the price of, any drug for which we obtain regulatory approval. Obtaining reimbursement for our drugs may be particularly difficult because of the higher prices often associated with drugs administered under the supervision of a physician. If reimbursement is not available or is available only to limited levels, we may not be able to successfully commercialize any drug candidate that we successfully develop.

There may be significant delays in obtaining reimbursement for approved drug candidates, and coverage may be more limited than the purposes for which the drug candidates are approved by the NMPA, the FDA or other comparable regulatory authorities. Moreover, eligibility for reimbursement does not imply that any drug will be paid for in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution. Interim payments for new drugs, if applicable, may also not be sufficient to cover our costs and may not be made permanent. Payment rates may vary according to the use of the drug and the clinical setting in which it is used, may be based on payments allowed for lower cost drugs that are already reimbursed, and may be incorporated into existing payments for other services. Net prices for drugs may be reduced by mandatory

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discounts or rebates required by government healthcare programs or private payors and by any future weakening of laws that presently restrict imports of drugs from countries where they may be sold at lower prices than in the United States. Our inability to promptly obtain coverage and profitable payment rates from both government-funded and private payors for any future approved drug candidates and any new drugs that we develop could have a material adverse effect on our business, our operating results, and our overall financial condition.

Current and future legislation may increase the difficulty and cost for us to obtain marketing approval of and commercialize our drug candidates and affect the prices we may obtain.

In the United States and certain other jurisdictions, there have been a number of legislative and regulatory changes and proposed changes regarding the healthcare system that could prevent or delay marketing approval of our drug candidates, restrict post-approval activities and affect our ability to sell profitably any drug candidates for which we obtain marketing approval.

The Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010, or collectively the ACA, became law. The ACA is a sweeping law intended to broaden access to health insurance, reduce or constrain the growth of healthcare spending, enhance remedies against fraud and abuse, add new transparency requirements for the healthcare and health insurance industries, impose new taxes and fees on the health industry and impose additional health policy reforms. Among the provisions of the ACA of importance to our drug candidates are the following:

Legislative and regulatory proposals have been made to expand post-approval requirements and restrict sales and promotional activities for pharmaceutical products. We cannot be sure whether additional legislative changes will be enacted, or whether the FDA regulations, guidance or interpretations will be changed, or what the impact of such changes on the marketing approvals, if any, of our drug candidates may be. In addition,

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increased scrutiny by the U.S. Congress of the FDA’s approval process may significantly delay or prevent marketing approval, as well as subject us to more stringent product labeling and post-marketing conditions and other requirements.

As we out-license some of our commercialization rights and engage in other forms of collaboration worldwide, including conducting clinical trials abroad, we may be exposed to specific risks of conducting our business and operations in international markets.

Markets outside of China form an important component of our growth strategy, as we out-license some of our commercialization rights to third parties outside the PRC and conduct certain of our clinical trials abroad. If we fail to obtain applicable licenses or fail to enter into strategic collaboration arrangements with third parties in these markets, or if these collaboration arrangements turn out unsuccessful, our revenue-generating growth potential will be adversely affected.

Moreover, international business relationships subject us to additional risks that may materially adversely affect our ability to attain or sustain profitable operations, including:

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These and other risks may materially adversely affect our ability to attain or sustain revenue from international markets.

If safety, efficacy, or other issues arise with any medical product that is used in combination with our drug candidates, we may be unable to market such drug candidate or may experience significant regulatory delays or supply shortages, and our business could be materially harmed.

We plan to develop certain of our drug candidates for use as a combination therapy. If the NMPA, the FDA or another comparable regulatory agency revokes its approval of another therapeutic we use in combination with our drug candidates, we will not be able to market our drug candidates in combination with such revoked therapeutic. If safety or efficacy issues arise with these or other therapeutics that we seek to combine with our drug candidates in the future, we may experience significant regulatory delays, and we may be required to redesign or terminate the applicable clinical trials. In addition, if manufacturing or other issues result in a supply shortage of any component of our combination drug candidates or if we cannot secure supply of any component of our drug candidates at commercially reasonable or acceptable prices, we may not be able to complete clinical development of our drug candidates on our current timeline or within our current budget, or at all.

Lack of third-party combination drugs may materially and adversely affect demand for our drugs.

Our drug candidates may be administered in combination with drugs of other pharmaceutical companies as one regimen. In addition, we often use such third-party drugs in our development and clinical trials as controls for our studies. As a result, both the results of our clinical trials and the sales of our drugs may be affected by the availability of these third-party drugs. If other pharmaceutical companies discontinue these combination drugs, regimens that use these combination drugs may no longer be prescribed, and we may not be able to introduce or find an alternative drug to be used in combination with our drugs at all or in a timely manner and on a cost-effective basis. As a result, demand for our drugs may be lowered, which would in turn materially and adversely affect our business and results of operations.

Risks Related to Our Reliance on Third Parties

As we rely on third parties to conduct our pre-clinical studies and clinical trials, if we lose our relationships with these third parties or if they do not successfully carry out their contractual duties or meet expected deadlines, we may not be able to obtain regulatory approval for or commercialize our drug candidates and our business could be substantially harmed.

We have relied on and plan to continue to rely on third-party contract research organization (“CROs”) to monitor and manage data for some of our ongoing pre-clinical and clinical programs. We rely on these parties for the execution of our pre-clinical and clinical trials, and control only certain aspects of their activities. Nevertheless, we are responsible for ensuring that each of our studies is conducted in accordance with the applicable protocol and legal, regulatory and scientific standards, and our reliance on the CROs does not relieve us of our regulatory responsibilities.

We also rely on third parties to assist in conducting our pre-clinical studies in accordance with Good Laboratory Practices (“GLP”). We and our CROs are required to comply with GCP, GLP and other regulatory regulations and guidelines enforced by the NMPA, the FDA and comparable foreign regulatory authorities for all of our drug candidates in clinical development. Regulatory authorities enforce these GCP, GLP or other

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regulatory requirements through periodic inspections of trial sponsors, investigators and trial sites. If we or any of our CROs fail to comply with applicable GCP, GLP or other regulatory requirements, the relevant data generated in our clinical trials may be deemed unreliable and the NMPA, the FDA or other comparable regulatory authorities may require us to perform additional clinical studies before approving our marketing applications. There can be no assurance that upon inspection by a given regulatory authority, such regulatory authority will determine that any of our clinical trials complies with GCP requirements. In addition, our clinical trials must be conducted with drug candidates or products produced under cGMP requirements. Failure to comply with these regulations may require us to repeat pre-clinical and clinical trials, which would delay the regulatory approval process.

Our CROs have the right to terminate their agreements with us in the event of an unrectified material breach. If any of our relationships with our third-party CROs is terminated, we may not be able to (i) enter into arrangements with alternative CROs or do so on commercially reasonable terms or (ii) meet our desired clinical development timelines. In addition, there is a natural transition period when a new CRO commences work, and the new CRO may not provide the same type or level of services as the original provider and data from our clinical trials may be compromised as a result. There is also a need for relevant technology to be transferred to the new CRO, which may take time and further delay our development timelines.

Except for remedies available to us under our agreements with our CROs, we cannot control whether or not our CROs devote sufficient time and resources to our ongoing clinical, nonclinical and pre-clinical programs. If our CROs do not successfully carry out their contractual duties or obligations or meet expected deadlines or if the quality or accuracy of the clinical data they obtain is compromised due to their failure to adhere to our clinical protocols, regulatory requirements or for other reasons, our clinical trials may be extended, delayed or terminated and we may not be able to obtain regulatory approval for or successfully commercialize our drug candidates. As a result, our results of operations and the commercial prospects for our drug candidates would be harmed and our costs could increase. In turn, our ability to generate revenues could be delayed or compromised.

Because we rely on third parties, our internal capacity to perform these functions is limited. Outsourcing these functions involves certain risks that third parties may not perform to our standards, may not produce results in a timely manner or may fail to perform at all. In addition, the use of third-party service providers requires us to disclose our proprietary information to these third parties, which could increase the risk that such information will be misappropriated. We currently have a small number of employees, which limits the internal resources we have available to identify and monitor our third-party service providers. To the extent we are unable to identify and successfully manage the performance of third-party service providers in the future, our business may be adversely affected. Though we carefully manage our relationships with our CROs, there can be no assurance that we will not encounter similar challenges or delays in the future or that these delays or challenges will not have a material adverse impact on our business, financial condition and prospects.

We expect to rely on third parties to manufacture at least a portion of our drug candidate supplies, and we intend to rely on third parties for at least a portion of the manufacturing process of our drug candidates, if approved. Our business could be harmed if those third parties fail to provide us with sufficient quantities of product or fail to do so at acceptable quality levels or prices.

Although we plan to either construct or acquire a facility that will be used as our clinical-scale manufacturing and processing facility, we intend to also partially rely on third-party vendors to manufacture supplies and process our drug candidates. We have not yet manufactured or processed our drug candidates on a commercial scale and may not be able to do so for any of our drug candidates. We have limited experience in managing the manufacturing process, and our process may be more difficult or expensive than the approaches currently in use.

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Our anticipated reliance on third-party manufacturers exposes us to certain risks, including, but not limited to, the following:

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Each of these risks could delay or prevent the completion of our clinical trials or the approval of any of our drug candidates by the NMPA, the FDA or other comparable regulatory authorities, result in higher costs or adversely impact the commercialization of our drug candidates. In addition, we will rely on third parties to perform certain specification tests on our drug candidates prior to delivery to patients. If these tests are not appropriately done and test data is not reliable, patients could be put at risk of serious harm and the NMPA, the FDA or other comparable regulatory authorities could place significant restrictions on our company until deficiencies are remedied.

The manufacture of biopharmaceutical products is complex and requires significant expertise and capital investment, including the development of advanced manufacturing techniques and process controls. Currently, our drug raw materials for our manufacturing activities are supplied by multiple source suppliers. We have agreements for the supply of drug materials with manufacturers or suppliers that we believe have sufficient capacity to meet our demands. In addition, we believe that adequate alternative sources for such supplies exist. However, there is a risk that, if supplies are interrupted, our business would be materially harmed.

Manufacturers of biopharmaceutical products often encounter difficulties in production, particularly in scaling up or out, validating the production process, and assuring high reliability of the manufacturing process, including the absence of contamination. These problems include logistics and shipping, difficulties with production costs and yields, quality control, including stability of the product, product testing, operator error and availability of qualified personnel, as well as compliance with strictly enforced regulations in the PRC, the United States and other applicable jurisdictions. Further, if contaminants are discovered in the supply of our drug candidates or in the manufacturing facilities, such manufacturing facilities may need to be closed for an extended period of time for us to investigate and remedy the contamination. There can be no assurance that any stability failures or other issues relating to the manufacture of our drug candidates will not occur in the future. Additionally, our contract manufacturers may experience manufacturing difficulties due to resource constraints or as a result of labor disputes or unstable political environment. If our contract manufacturers were to encounter any of these difficulties, or otherwise fail to comply with their contractual obligations, our ability to provide our drug candidate to patients in clinical trials would be jeopardized. Any delay or interruption in the supply of clinical trial supplies could delay the completion of our clinical trials, increase the costs associated with maintaining clinical trial programs and, depending upon the period of delay, require us to begin new clinical trials at additional expense or terminate clinical trials completely.

We have entered into collaborations and may form or seek collaborations or strategic alliances or enter into additional licensing arrangements in the future, and we may not realize the benefits of such alliances or licensing arrangements.

We may form or seek strategic alliances, create joint ventures or collaborations, or enter into additional licensing arrangements with third parties that we believe will complement or augment our development and commercialization efforts with respect to our drug candidates and any future drug candidates that we may develop. Any of these relationships may require us to incur recurring or non-recurring expenses and other charges, increase our near and long-term expenditures, issue securities that dilute the value of our ADSs, or disrupt our management and business. For example, we have entered into a license and collaboration agreement with MorphoSys AG (“MorphoSys”), pursuant to which we in-licensed from MorphoSys the development and commercialization rights of felzartamab in Greater China. Another example is our collaboration with AbbVie. In September 2020, we granted AbbVie a global license, excluding Mainland China, Hong Kong and Macau, to develop and commercialize lemzoparlimab (as well as certain other compounds directed against CD47), and we will retain all rights to develop and commercialize lemzoparlimab in Mainland China, Hong Kong and Macau. The effectiveness of the contract with AbbVie is subject to our performance of certain contractual obligations and regulatory approval; such approval may not be obtained or may be delayed, which could result in a detrimental effect on our collaboration. For a more detailed discussion, please see “Business—Our Global Strategic Collaborations—Global Strategic Partnership with AbbVie.” In addition, we face significant competition in seeking appropriate strategic partners and the negotiation process is time-consuming and complex.

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Moreover, we may not be successful in our efforts to establish a strategic partnership or other alternative arrangements for our drug candidates because they may be deemed to be at too early a stage of development for collaborative effort and third parties may not view our drug candidates as having the requisite potential to demonstrate safety and efficacy. If and when we collaborate with a third party for the development and commercialization of a drug candidate, we can expect to relinquish some or all of the control over the future success of that drug candidate to the third party.

Further, collaborations involving our drug candidates are subject to specific risks, which include, but are not limited to, the following:

As a result, if we enter into collaboration agreements and strategic partnerships or license our drugs, we may not be able to realize the benefit of such transactions if we are unable to successfully integrate these agreements or partnerships with our existing operations and company culture, which could delay our timelines or otherwise adversely affect our business.

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Neither can we be certain that, following a strategic transaction or license, we will be able to achieve the revenue or specific net income that justifies such transaction. If we are unable to reach agreements with suitable collaborators on a timely basis, on acceptable terms, or at all, we may have to curtail the development of a drug candidate, reduce or delay its development program or one or more of our other development programs, delay its potential commercialization or reduce the scope of any sales or marketing activities, or increase our expenditures and undertake development or commercialization activities at our own expense. If we elect to fund and undertake development or commercialization activities on our own, we may need to obtain additional expertise and additional capital, which may not be available to us on acceptable terms or at all. If we fail to enter into collaborations and do not have sufficient funds or expertise to undertake the necessary development and commercialization activities, we may not be able to further develop our drug candidates or bring them to market and generate product sales revenue, which would harm our business, financial condition, results of operations and prospects.

Risks Related to Our Intellectual Property

If we are unable to obtain and maintain patent and other intellectual property protection for our drug candidates, or if the scope of such intellectual property rights obtained is not sufficiently broad, third parties could develop and commercialize products and technologies similar or identical to ours and compete directly against us, and our ability to successfully commercialize any product or technology may be adversely affected.

Our success depends in large part on our ability to protect our proprietary technology and drug candidates from competition by obtaining, maintaining, defending and enforcing our intellectual property rights, including patent rights. As of September 30, 2020, our owned patent portfolio consists of 11 issued patents and 223 patent applications primarily in connection with the drug candidates in our Global Portfolio, including 12 Patent Cooperation Treaty (“PCT”) patent applications, 16 U.S. patent applications, 18 PRC patent applications and 177 patent applications in other jurisdictions. In addition, as of September 30, 2020, we in-licensed the Greater China and Korea rights relating to 22 issued patents and 34 pending patent applications primarily in connection with felzartamab, eftansomatropin, olamkicept, enoblituzumab and efineptakin. We seek to protect the drug candidates and technology that we consider commercially important by filing patent applications in China, the United States and other countries or regions, relying on trade secrets or pharmaceutical regulatory protection or employing a combination of these methods. This process is expensive and time-consuming, and we or our licensors may not be able to file and prosecute all necessary or desirable patent applications in all jurisdictions at a reasonable cost or in a timely manner. It is also possible that we or our licensors will fail to identify patentable aspects of our research and development output before it is too late to obtain patent protection.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex legal and factual questions and has in recent years been the subject of much litigation. As a result, the issuance, scope, validity, enforceability and commercial value of our patent rights are highly uncertain. Our pending and future patent applications may not result in patents being issued which protect our technology or drug candidates or which effectively prevent others from commercializing competitive technologies and drug candidates. The patent examination process may require us or our licensors to narrow the scope of the claims of our or our licensors’ pending and future patent applications, which may limit the scope of patent protection that may be obtained. We cannot assure that all of the potentially relevant prior art relating to our patents and patent applications has been found. If such prior art exists, it can invalidate a patent or prevent a patent application from being issued as a patent.

Even if patents do issue on any of these applications, there can be no assurance that a third party will not challenge their validity, enforceability, or scope, which may result in the patent claims being narrowed or invalidated, or that we will obtain sufficient claim scope in those patents to prevent a third party from competing successfully with our drug candidates. We may become involved in interference, inter partes review, post grant review, ex parte reexamination, derivation, opposition or similar other proceedings challenging our patent rights or the patent rights of others. An adverse determination in any such proceeding could reduce the scope of, or

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invalidate, our patent rights, allow third parties to commercialize our technology or drug candidates and compete directly with us, or result in our inability to manufacture or commercialize drug candidates without infringing third-party patent rights. Thus, even if our patent applications issue as patents, they may not issue in a form that will provide us with any meaningful protection, prevent competitors from competing with us or otherwise provide us with any competitive advantage.

Our competitors may be able to circumvent our patents by developing similar or alternative technologies or drug candidates in a non-infringing manner. The issuance of a patent is not conclusive as to its scope, validity or enforceability, and our owned and licensed patents may be challenged in the courts or patent offices in the United States and other countries. Such challenges may result in patent claims being narrowed, invalidated or held unenforceable, which could limit our ability to stop or prevent us from stopping others from using or commercializing similar or identical technology and drug candidates, or limit the duration of the patent protection of our technology and drug candidates. Given the amount of time required for the development, testing and regulatory review of new drug candidates, patents protecting such assets might expire before or shortly after such assets are commercialized. As a result, our patent portfolio may not provide us with sufficient rights to exclude others from commercializing drug candidates similar or identical to ours.

Changes in either the patent laws or interpretation of the patent laws in the United States and other countries may diminish the value of our patents or narrow the scope of our patent protection. Under the America Invents Act (“AIA”) enacted in 2011, the United States moved to this first-to-file system in early 2013 from the previous system under which the first to make the claimed invention was entitled to the patent. Assuming the other requirements for patentability are met, the first to file a patent application is entitled to the patent. Publications of discoveries in the scientific literature often lag behind the actual discoveries, and patent applications in the United States and other jurisdictions are typically not published until 18 months after filing, or in some cases not at all. Therefore, we cannot be certain that we were the first to make the inventions claimed in our patents or pending patent applications, or that we were the first to file for patent protection of such inventions.

We enjoy only limited geographical protection with respect to certain patents and may not be able to protect our intellectual property rights throughout the world, including in the PRC.

Filing and prosecuting patent applications and defending patents covering our drug candidates in all countries throughout the world could be prohibitively expensive. Competitors may use our and our licensors’ technologies in jurisdictions where we have not obtained patent protection to develop their own drug candidates and, further, may export otherwise infringing drug candidates to territories, including the PRC, where we and our licensors have patent protection, but enforcement rights are not as strong as that in the United States or Europe. These drug candidates may compete with our drug candidates, and our and our licensors’ patents or other intellectual property rights may not be effective or sufficient to prevent them from competing.

The laws of some jurisdictions, including the PRC, do not protect intellectual property rights to the same extent as the laws or rules and regulations in the United States and Europe, and many companies have encountered significant difficulties in protecting and defending such rights in such jurisdictions. The legal systems of certain countries, particularly certain developing countries, do not favor the enforcement of patents, trade secrets and other intellectual property protection, which could make it difficult for us to stop the infringement of our patents or marketing of competing drug candidates in violation of our proprietary rights generally. Proceedings to enforce our patent rights in other jurisdictions, whether or not successful, could result in substantial costs and divert our efforts and attention from other aspects of our business, could put our patents at risk of being invalidated or interpreted narrowly and our patent applications at risk of not issuing as patents, and could provoke third parties to assert claims against us. We may not prevail in any lawsuits that we initiate and the damages or other remedies awarded, if any, may not be commercially meaningful. Accordingly, our efforts to enforce our intellectual property rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license. Furthermore, while we intend to protect our intellectual property rights in our expected significant markets, we cannot ensure that we will be able

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to initiate or maintain similar efforts in all jurisdictions in which we may wish to market our drug candidates. Accordingly, our efforts to protect our intellectual property rights in such countries may be inadequate, which may have an adverse effect on our ability to successfully commercialize our drug candidates in all of our expected significant foreign markets. If we or our licensors encounter difficulties in protecting, or are otherwise precluded from effectively protecting, the intellectual property rights important for our business in such jurisdictions, the value of these rights may be diminished and we may face additional competition from others in those jurisdictions.

Some countries also have compulsory licensing laws under which a patent owner may be compelled to grant licenses to third parties. In addition, some countries limit the enforceability of patents against government agencies or government contractors. In those countries, the patent owner may have limited remedies, which could materially diminish the value of such patents. If we or any of our licensors is forced to grant a license to third parties with respect to any patents relevant to our business, our competitive position may be impaired.

Obtaining and maintaining our patent protection depends on compliance with various procedural, document submission, fee payment, and other requirements imposed by governmental patent agencies, and our patent protection could be reduced or eliminated for non-compliance with these requirements.

Periodic maintenance and annuity fees on any issued patent are due to be paid to the United States Patent and Trademark Office (“USPTO”) and foreign patent agencies over the lifetime of a patent. In addition, the USPTO and other foreign patent agencies require compliance with a number of procedural, documentary, fee payment, and other similar provisions during the patent application process. While an inadvertent failure to make payment of such fees or to comply with such provisions can in many cases be cured by payment of a late fee or by other means in accordance with the applicable rules, there are situations in which such non-compliance will result in the abandonment or lapse of the patent or patent application, and the partial or complete loss of patent rights in the relevant jurisdiction. Non-compliance events that could result in abandonment or lapse of a patent or patent application include failure to respond to official actions within prescribed time limits, and non-payment of fees and failure to properly legalize and submit formal documents within prescribed time limits. If we or our licensors fail to maintain the patents and patent applications covering our drug candidates or if we or our licensors otherwise allow our patents or patent applications to be abandoned or lapse, our competitors might be able to enter the market, which would hurt our competitive position and could impair our ability to successfully commercialize our drug candidates in any indication for which they are approved.

Our owned and in-licensed patents and other intellectual property may be subject to further priority disputes or to inventorship disputes and similar proceedings. If we or our licensors are unsuccessful in any of these proceedings, we may be required to obtain licenses from third parties, which may not be available on commercially reasonable terms or at all, or to modify or cease the development, manufacture and commercialization of one or more of the drug candidates we may develop, which could have a material adverse impact on our business.

We or our licensors may be subject to claims that former employees, collaborators or other third parties have an interest in our owned or in-licensed patents or other intellectual property as an inventor or co-inventor. If we or our licensors are unsuccessful in any interference proceedings or other priority or validity disputes (including any patent oppositions) to which we or they are subject, we may lose valuable intellectual property rights through the loss of one or more patents owned or licensed or our owned or licensed patent claims may be narrowed, invalidated, or held unenforceable. In addition, if we or our licensors are unsuccessful in any inventorship disputes to which we or they are subject, we may lose valuable intellectual property rights, such as exclusive ownership of, or the exclusive right to use, our owned or in-licensed patents. If we or our licensors are unsuccessful in any interference proceeding or other priority or inventorship dispute, we may be required to obtain and maintain licenses from third parties, including parties involved in any such interference proceedings or other priority or inventorship disputes. Such licenses may not be available on commercially reasonable terms or at all, or may be non-exclusive. If we are unable to obtain and maintain such licenses, we may need to modify

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or cease the development, manufacture, and commercialization of one or more of our drug candidates. The loss of exclusivity or the narrowing of our owned and licensed patent claims could limit our ability to stop others from using or commercializing similar or identical drug products. Any of the foregoing could result in a material adverse effect on our business, financial condition, results of operations, or prospects. Even if we are successful in an interference proceeding or other similar priority or inventorship disputes, it could result in substantial costs and be a distraction to our management and other employees.

Claims that our drug candidates or the sale or use of our future products infringe, misappropriate or otherwise violate the patents or other intellectual property rights of third parties could result in costly litigation or could require substantial time and money to resolve, even if litigation is avoided.

We cannot guarantee that our drug candidates or the sale or use of our future products do not and will not in the future infringe, misappropriate or otherwise violate third-party patents or other intellectual property rights. Third parties might allege that we are infringing their patent rights or that we have misappropriated their trade secrets, or that we are otherwise violating their intellectual property rights, whether with respect to the manner in which we have conducted our research, or with respect to the use or manufacture of the compounds we have developed or are developing. Litigation relating to patents and other intellectual property rights in the biopharmaceutical and pharmaceutical industries is common, including patent infringement lawsuits. The various markets in which we plan to operate are subject to frequent and extensive litigation regarding patents and other intellectual property rights. Some claimants may have substantially greater resources than we have and may be able to sustain the costs of complex intellectual property litigation to a greater degree and for longer periods of time than we could. Third parties might resort to litigation against us or other parties we have agreed to indemnify, which litigation could be based on either existing intellectual property or intellectual property that arises in the future. For example, we are aware of a third-party U.S. patent and its counterpart European patents that relate to the use of antibodies having specificity to PD-L1 to treat cancer.

It is also possible that we failed to identify, or may in the future fail to identify, relevant patents or patent applications held by third parties that cover our drug candidates. Publication of discoveries in the scientific or patent literature often lags behind actual discoveries. Therefore, we cannot be certain that we were the first to invent, or the first to file patent applications on, our drug candidates or for their uses, or that our drug candidates will not infringe patents that are currently issued or that are issued in the future. In the event that a third party has also filed a patent application covering one of our drug candidates or a similar invention, our patent application may be regarded as a competing application and may not be approved in the end. Additionally, pending patent applications that have been published can, subject to certain limitations, be later amended in a manner that could cover our products or their use.

If a third party were to assert claims of patent infringement against us, even if we believe such third-party claims are without merit, a court of competent jurisdiction could hold that these third-party patents are valid, enforceable and infringed, and the holders of any such patents may be able to block our ability to commercialize the applicable product unless we obtained a license under the applicable patents, or until such patents expire or are finally determined to be invalid or unenforceable. Similarly, if any third-party patents were held by a court of competent jurisdiction to cover aspects of our compositions, formulations, or methods of treatment, prevention, or use, the holders of any such patents may be able to block our ability to develop and commercialize the applicable product unless we obtained a license or until such patent expires or is finally determined to be invalid or unenforceable. In addition, defending such claims would cause us to incur substantial expenses and could cause us to pay substantial damages, if we are found to be infringing a third party’s patent rights. These damages potentially include increased damages and attorneys’ fees if we are found to have infringed such rights willfully. In order to avoid or settle potential claims with respect to any patent or other intellectual property rights of third parties, we may choose or be required to seek a license from a third party and be required to pay license fees or royalties or both, which could be substantial. These licenses may not be available on acceptable terms, or at all. Even if we were able to obtain a license, the rights may be nonexclusive, which could result in our competitors gaining access to the same intellectual property. Ultimately, we could be prevented from commercializing a drug

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candidate, or be forced, by court order or otherwise, to modify or cease some or all aspects of our business operations, if, as a result of actual or threatened patent or other intellectual property claims, we are unable to enter into licenses on acceptable terms. Further, we could be found liable for significant monetary damages as a result of claims of intellectual property infringement.

Defending against claims of patent infringement, misappropriation of trade secrets or other violations of intellectual property rights could be costly and time-consuming, regardless of the outcome. Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation. Thus, even if we were to ultimately prevail, or to settle at an early stage, such litigation could burden us with substantial unanticipated costs.

Issued patents covering one or more of our drug candidates could be found invalid or unenforceable if challenged in court.

Despite measures we take to obtain and maintain patent and other intellectual property rights with respect to our drug candidates, our intellectual property rights could be challenged or invalidated. For example, if we were to initiate legal proceedings against a third party to enforce a patent covering one of our drug candidates, the defendant could counterclaim that our patent is invalid and/or unenforceable. Grounds for a validity challenge could be an alleged failure to meet any of several statutory requirements, for example, lack of novelty, obviousness or non-enablement. Grounds for an unenforceability assertion could be an allegation that someone connected with prosecution of the patent withheld relevant information from the USPTO, SIPO, or the applicable foreign counterpart, or made a misleading statement, during prosecution. Although we believe that we have conducted our patent prosecution in accordance with a duty of candor and in good faith, the outcome following legal assertions of invalidity and unenforceability during patent litigation is unpredictable. If a defendant were to prevail on a legal assertion of invalidity and/or unenforceability, we would lose at least part, and perhaps all, of the patent protection on a drug candidate. Even if a defendant does not prevail on a legal assertion of invalidity and/or unenforceability, our patent claims may be construed in a manner that would limit our ability to enforce such claims against the defendant and others. Even if we establish infringement, the court may decide not to grant an injunction against further infringing activity and instead award only monetary damages, which may not be an adequate remedy. In addition, if the breadth or strength of protection provided by our patents is threatened, it could dissuade companies from collaborating with us to license, develop, or commercialize our current or future drug candidates. Any loss of patent protection could have a material adverse impact on one or more of our drug candidates and our business.

Enforcing our intellectual property rights against third parties may also cause such third parties to file other counterclaims against us, which could be costly to defend and could require us to pay substantial damages, cease the sale of certain drugs or enter into a license agreement and pay royalties (which may not be possible on commercially reasonable terms or at all).

Intellectual property litigation may lead to unfavorable publicity which may harm our reputation and cause the market price of our ADSs to decline, and any unfavorable outcome from such litigation could limit our research and development activities and/or our ability to commercialize our drug candidates.

During the course of any intellectual property litigation, there could be public announcements of the results of hearings, rulings on motions, and other interim proceedings in the litigation. If securities analysts or investors regard these announcements as negative, the perceived value of our drug candidates, future drugs, programs or intellectual property could be diminished. Accordingly, the market price of our ADSs may decline. Such announcements could also harm our reputation or the market for our drug candidates, which could have a material adverse effect on our business.

In the event of intellectual property litigation, there can be no assurance that we would prevail, even if the case against us is weak or flawed. If third parties successfully assert their intellectual property rights against us,

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prohibitions against using certain technologies, or prohibitions against commercializing our drug candidates, could be imposed by a court or by a settlement agreement between us and a plaintiff. In addition, if we are unsuccessful in defending against allegations that we have infringed, misappropriated or otherwise violated the patent or other intellectual property rights of others, we may be forced to pay substantial damage awards to the plaintiff. Additionally, we may be required to obtain a license from the intellectual property owner in order to continue our research and development programs or to commercialize any resulting product. It is possible that the necessary license will not be available to us on commercially acceptable terms, or at all. This may not be technically or commercially feasible, may render our products less competitive, or may delay or prevent the launch of our products to the market. Any of the foregoing could limit our research and development activities, our ability to commercialize one or more drug candidates, or both.

Most of our competitors are larger than we are and have substantially greater resources. They are, therefore, likely to be able to sustain the costs of complex intellectual property litigation longer than we could. In addition, the uncertainties associated with litigation could have a material adverse effect on our ability to raise the funds necessary to conduct our clinical trials, continue our internal research programs, in-license needed technology, or enter into strategic partnerships that would help us bring our drug candidates to market.

In addition, any future intellectual property litigation, interference or other administrative proceedings will result in additional expense and distraction of our personnel. An adverse outcome in such litigation or proceedings may expose us or any future strategic partners to loss of our proprietary position, expose us to significant liabilities, or require us to seek licenses that may not be available on commercially acceptable terms, if at all, each of which could have a material adverse effect on our business.

Changes in patent law could diminish the value of patents in general, thereby impairing our ability to protect our drug candidates.

As is the case with other biopharmaceutical companies, our success is heavily dependent on intellectual property, particularly patent rights. Obtaining and enforcing patents in the biopharmaceutical industry involves both technological and legal complexity, and is therefore costly, time-consuming, and inherently uncertain. In addition, the United States has recently enacted and is implementing wide-ranging patent reform legislation. Recent U.S. Supreme Court rulings have narrowed the scope of patent protection available in certain circumstances and weakened the rights of patent owners in certain situations. In addition to increasing uncertainty with regard to our ability to obtain patents in the future, this combination of events has created uncertainty with respect to the value of patents once obtained, if any. Depending on decisions by the U.S. Congress, the federal courts and the USPTO, the laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future. For example, in a recent case, Assoc. for Molecular Pathology v. Myriad Genetics, Inc., the U.S. Supreme Court held that certain claims to naturally-occurring substances are not patentable. Although we do not believe that our currently issued patents and any patents that may issue from our pending patent applications directed to our drug candidates if issued in their currently pending forms, as well as patent rights licensed by us, will be found invalid based on this decision, we cannot predict how future decisions by the courts, the U.S. Congress or the USPTO may impact the value of our patent rights. There could be similar changes in the laws of foreign jurisdictions that may impact the value of our patent rights or our other intellectual property rights.

If we are unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed. We also may be subject to claims that our employees, consultants, or advisers have wrongfully used or disclosed alleged trade secrets of their former employers or claims asserting ownership of what we regard as our own intellectual property.

In addition to our issued patents and pending patent applications, we rely on trade secret and confidential information, including unpatented know-how, technology and other proprietary information, to maintain our

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competitive position and to protect our drug candidates. We seek to protect this trade secret and confidential information, in part, by entering into non-disclosure and confidentiality agreements with parties that have access to them, such as our employees, corporate collaborators, outside scientific collaborators, sponsored researchers, contract manufacturers, consultants, advisers and other third parties. We also enter into confidentiality and invention or patent assignment agreements with our employees and consultants. However, any of these parties may breach such agreements and disclose our proprietary information, and we may not be able to obtain adequate remedies for such breaches. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret can be difficult, expensive and time-consuming, and the outcome is unpredictable. If any of our trade secrets were to be lawfully obtained or independently developed by a competitor or other third party, we would have no right to prevent them from using that technology or information to compete with us and our competitive position would be harmed.

Furthermore, many of our employees, consultants, and advisers, including our senior management, were previously employed at other biotechnology or pharmaceutical companies, including our competitors or potential competitors. Some of these employees, consultants, and advisers, including members of our senior management, executed proprietary rights, non-disclosure and non-competition agreements in connection with such previous employment. Although we try to ensure that our employees do not use the proprietary information or know-how of others in their work for us, we may be subject to claims that we or these employees have used or disclosed intellectual property, including trade secrets or other proprietary information, of any such individual’s former employer. We are not aware of any threatened or pending claims related to these matters or concerning the agreements with our senior management, but in the future litigation may be necessary to defend against such claims. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel. Even if we are successful in defending against such claims, litigation could result in substantial costs and be a distraction to management. In addition, while we typically require our employees, consultants and contractors who may be involved in the development of intellectual property to execute agreements assigning such intellectual property to us, we may be unsuccessful in executing such an agreement with each party who in fact develops intellectual property that we regard as our own, and furthermore, the assignment of intellectual property rights may not be self-executing, or the assignment agreements may be breached, each of which may result in claims by or against us related to the ownership of such intellectual property. If we fail in prosecuting or defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights. Even if we are successful in prosecuting or defending against such claims, litigation could result in substantial costs, be a distraction to our management and scientific personnel and have a material adverse effect on our business, financial condition, results of operations and prospects.

We may not be successful in obtaining or maintaining necessary rights for our development pipeline through acquisitions and in-licenses.

Because our programs may involve additional drug candidates that may require the use of proprietary rights held by third parties, the growth of our business may depend in part on our ability to acquire and maintain licenses or other rights to use these proprietary rights. We may be unable to acquire or in-license any compositions, methods of use, or other intellectual property rights from third parties that we identify. The licensing and acquisition of third-party intellectual property rights is a competitive area, and a number of more established companies are also pursuing strategies to license or acquire third-party intellectual property rights that we may consider attractive or necessary. These established companies may have a competitive advantage over us due to their size, cash resources and greater clinical development and commercialization capabilities. In addition, companies that perceive us to be a competitor may be unwilling to assign or license rights to us. We also may be unable to license or acquire third-party intellectual property rights on terms that would allow us to make an appropriate return on our investment or at all. If we are unable to successfully obtain rights to required third-party intellectual property rights or maintain the existing intellectual property rights we have, we may have to abandon development of the relevant program or drug candidate, which could have a material adverse effect on our business, financial condition, results of operations and prospects for growth.

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Our rights to develop and commercialize our drug candidates are subject, in part, to the terms and conditions of licenses granted to us by others.

We rely on licenses to certain patent rights and other intellectual property from third parties that are important or necessary to the development of our drug candidates. These and other licenses may not provide exclusive rights to use such intellectual property in all relevant fields of use and in all territories in which we may wish to develop or commercialize our drug products. As a result, we may not be able to prevent competitors from developing and commercializing competitive drug products in territories included in all of our licenses.

We may not have the right to control the preparation, filing, prosecution, maintenance, enforcement, and defense of patents and patent applications covering the drug candidates that we license from third parties. Moreover, we have not had and do not have primary control over these activities for certain of our patents or patent applications and other intellectual property rights that we jointly own with certain of our licensors and sub-licensors. Therefore, we cannot be certain that these patents and patent applications will be prepared, filed, prosecuted, maintained, enforced, and defended in a manner consistent with the best interests of our business. If our licensors fail to prosecute, maintain, enforce and defend such patents, or lose rights to those patents or patent applications, the rights we have licensed may be reduced or eliminated, and our right to develop and commercialize any of our drugs that are subject of such licensed rights could be adversely affected.

Pursuant to the terms of the license agreements with some of our licensors, the licensors may have the right to control enforcement of our licensed patents or defense of any claims asserting the invalidity or unenforceability of these patents. Even if we are permitted to pursue the enforcement or defense of our licensed patents, we will require the cooperation of our licensors and any applicable patent owners and such cooperation may not be provided to us. We cannot be certain that our licensors will allocate sufficient resources or prioritize their or our enforcement of such patents or defense of such claims to protect our interests in the licensed patents. Even if we are not a party to these legal actions, an adverse outcome could harm our business because it might prevent us from continuing to license intellectual property that we may need to operate our business. If we lose any of our licensed intellectual property, our right to develop and commercialize any of our drug candidates that are subject of such licensed rights could be adversely affected.

In addition, our licensors may have relied on third party consultants or collaborators or on funds from third parties such that our licensors are not the sole and exclusive owners of the patents we in-license. This could have a material adverse effect on our competitive position, business, financial conditions, results of operations, and prospects.

In spite of our best efforts, our licensors might conclude that we have materially breached our license agreements and might therefore terminate the license agreements, thereby removing our ability to develop and commercialize drug products covered by these license agreements. If such licenses are terminated, we may be required seek alternative in-license arrangements, which may not be available on commercially reasonable terms or at all, or may be non-exclusive. If these in-licenses are terminated, or if the underlying patents fail to provide the intended exclusivity, we may need to modify or cease the development, manufacture, and commercialization of one or more of our drug candidates and competitors would have the freedom to seek regulatory approval of, and to market, products identical to ours. In addition, we may seek to obtain additional licenses from our licensors and, in connection with obtaining such licenses, we may agree to amend our existing licenses in a manner that may be more favorable to the licensors, including by agreeing to terms that could enable third parties (potentially including our competitors) to receive licenses to a portion of the intellectual property that is subject to our existing licenses. Any of these events could have a material adverse effect on our competitive position, business, financial conditions, results of operations, and prospects.

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If we fail to comply with our obligations in the agreements under which we license intellectual property rights from third parties or otherwise experience disruptions to our business relationships with our licensors, we could be required to pay monetary damages or could lose license rights that are important to our business.

Our business relies, in large part, on our ability to develop and commercialize drug candidates we have licensed from third parties, and we have entered into license agreements with third parties providing us with rights to various third-party intellectual property, including rights in patents and patent applications. Our licenses may not encumber all intellectual property rights owned or controlled by the affiliates of our licensors and relevant to our drug candidates, and we may need to obtain additional licenses from our existing licensors and others to advance our research or allow commercialization of drug candidates we may develop. In such case, we may need to obtain additional licenses which may not be available on an exclusive basis, on commercially reasonable terms or at a reasonable cost, if at all. In that event, we may be required to expend significant time and resources to redesign our drug candidates or the methods for manufacturing them or to develop or license replacement technology, all of which may not be feasible on a technical or commercial basis. If we are unable to do so, we may be unable to develop or commercialize the affected drug candidates, which could harm our business, financial condition, results of operations, and prospects significantly.

In addition, if our licensors breach the license agreements, we may not be able to enforce such agreements against our licensors’ parent entity or affiliates. Under each of our license and intellectual property-related agreements, in exchange for licensing or sublicensing us the right to develop and commercialize the applicable drug candidates, our licensors will be eligible to receive from us milestone payments, tiered royalties from commercial sales of such drug candidates, assuming relevant approvals from government authorities are obtained, or other payments. Our license and intellectual property-related agreements also require us to comply with other obligations including development and diligence obligations, providing certain information regarding our activities with respect to such drug candidates and/or maintaining the confidentiality of information we receive from our licensors.

If we fail to comply with our obligations under our current or future license agreements, our counterparties may have the right to terminate these agreements and, upon the effective date of such termination, have the right to re-obtain the licensed and sub-licensed technology and intellectual property. If any of our licensors terminate any of our licenses, we might not be able to develop, manufacture or market any drug or drug candidate that is covered by the licenses provided for under these agreements and other third parties may be able to market drug candidates similar or identical to ours. In such case, we may have to negotiate new or reinstated agreements with less favorable terms, and may be required to provide a grant back license to the licensors under our own intellectual property with respect to the terminated products. We may also face claims for monetary damages or other penalties under these agreements. While we would expect to exercise all rights and remedies available to us, including seeking to cure any breach by us, and otherwise seek to preserve our rights under the intellectual property rights licensed and sublicensed to us, we may not be able to do so in a timely manner, at an acceptable cost or at all. In particular, some of the milestone payments are payable upon our drug candidates reaching development milestones before we have commercialized, or received any revenue from, sales of such drug candidate, and we cannot guarantee that we will have sufficient resources to make such milestone payments. Any uncured, material breach under the license agreements could result in our loss of exclusive rights and may lead to a complete termination of our rights to the applicable drug candidate. Any of the foregoing could have a material adverse effect on our business, financial conditions, results of operations, and prospects.

It is possible that we may be unable to obtain any additional licenses at a reasonable cost or on reasonable terms, if at all. Certain of our license agreements also require us to meet development thresholds to maintain the license, including establishing a set timeline for developing and commercializing products. Disputes may arise regarding intellectual property subject to a license agreement, including:

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In addition, the agreements under which we license intellectual property or technology from third parties are complex, and certain provisions in such agreements may be susceptible to multiple interpretations. The resolution of any contract interpretation disagreement that may arise could narrow what we believe to be the scope of our rights to the relevant intellectual property or technology, or increase what we believe to be our financial or other obligations under the relevant agreement, either of which could have a material adverse effect on our business, financial condition, results of operations, and prospects. Moreover, if disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensing arrangements on commercially acceptable terms, we may be unable to successfully develop and commercialize the affected drug candidates, which could have a material adverse effect on our business, financial condition, results of operations and prospects.

Intellectual property rights do not necessarily protect us from all potential threats to our competitive advantage.

The degree of future protection afforded by our intellectual property rights is uncertain because intellectual property rights have limitations, and may not adequately protect our business, or permit us to maintain our competitive advantage. The following examples are illustrative:

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Any of the aforementioned threats to our competitive advantage could have a material adverse effect on our business and future prospects.

If our trademarks and trade names are not adequately protected, we may not be able to build name recognition in our markets of interest and our competitive position may be adversely affected.

We own registered trademarks. We may not be able to obtain trademark protection in territories that we consider of significant importance to us. In addition, any of our trademarks or trade names, whether registered or unregistered, may be challenged, opposed, infringed, cancelled, circumvented or declared generic, or determined to be infringing on other marks, as applicable. We may not be able to protect our rights to these trademarks and trade names, which we will need to build name recognition by potential collaborators or customers in our markets of interest. Over the long term, if we are unable to establish name recognition based on our trademarks and trade names, we may not be able to compete effectively and our business may be adversely affected.

Terms of our future patents may not be sufficient to effectively protect our drug candidates and business.

In many countries where we file applications for patents, the term of an issued patent is generally 20 years from the earliest claimed filing date of a non-provisional patent application in the applicable country. Although various extensions may be available, the life of a patent and the protection it affords are limited. Even if we obtain patents covering our drug candidates, we may still be open to competition from other companies, as well as generic medications once the patent life has expired for a drug. While there are patent regulations in the PRC in respect of regulatory data protection of new drugs containing new chemical components, there are currently no other clear mechanisms providing patent term extension or patent linkages for other drugs in the PRC. Therefore, it is possible that a lower-cost generic drug can emerge onto the market much more quickly. PRC regulators have set out a framework for integrating patent linkage and data exclusivity into the PRC regulatory regime, as well as for establishing a pilot program for patent term extension. This framework will require adoption of regulations to be implemented, although no such regulations have been issued to date. These factors may result in weaker protection for us against generic competition in the PRC than could be available to us in other jurisdictions, such as the United States. In addition, patents which we expect to obtain in the PRC may not be eligible to be extended for patent terms lost during clinical trials and the regulatory review process.

If we are unable to obtain patent term extensions or if such extensions are less than requested for, our competitors may obtain approval of competing products following our patent expirations and our business, financial condition, results of operations and prospects could be materially harmed as a result.

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If we do not obtain additional protection under the Hatch-Waxman Amendments and similar legislation in other countries extending the terms of our patents, if issued, relating to our drug candidates, our business may be materially harmed.

Depending upon the timing, duration and specifics of FDA regulatory approval for our drug candidates, one or more of our U.S. patents, if issued, may be eligible for limited patent term restoration under the Drug Price Competition and Patent Term Restoration Act of 1984 (the “Hatch-Waxman Amendments”). The Hatch-Waxman Amendments permit a patent term extension of up to five years as compensation for patent term lost during drug development and the FDA regulatory review process. Patent term extensions, however, cannot extend the remaining term of a patent beyond a total of 14 years from the date of drug approval by the FDA, and only one patent can be extended for a particular drug.

The application for patent term extension is subject to approval by the USPTO, in conjunction with the FDA. We may not be granted an extension because of, for example, failing to apply within applicable deadlines, failing to apply prior to expiration of relevant patents or otherwise failing to satisfy applicable requirements. Moreover, the applicable time period or the scope of patent protection afforded could be less than we request. If we are unable to obtain a patent term extension for a given patent or the term of any such extension is less than we request, the period during which we will have the right to exclusively market our drug will be shortened and our competitors may obtain earlier approval of competing drugs, and our ability to generate revenues could be materially adversely affected.

Risks Related to Our Industry, Business and Operations

Our future success depends on our ability to attract, retain and motivate senior management and qualified scientific employees.

We are highly dependent on the expertise of the members of our research and development team, as well as the principal members of our management. We have entered into employment agreements with our executive officers, but each of them may terminate their employment with us at any time with prior written notice. In addition, we currently do not have “key-man” insurance for any of our executive officers or other key personnel.

Recruiting, retaining and motivating qualified management, scientific, clinical, manufacturing and sales and marketing personnel will also be critical to our success. The loss of the services of our executive officers or other key employees could impede the achievement of our research, development and commercialization objectives and seriously harm our ability to successfully implement our business strategy. Further, replacing executive officers and key employees may be difficult and may take an extended period of time because of the limited number of individuals in our industry with the breadth of skills and experience required to successfully develop, gain regulatory approval of and commercialize drugs. Competition to hire from this limited pool is intense, and we may be unable to hire, train, retain or motivate these key personnel on acceptable terms given the competition among numerous biopharmaceutical companies for similar personnel. We also experience competition for the hiring of scientific and clinical personnel from universities and research institutions. In addition, our management will be required to devote significant time to new compliance initiatives from our status as a public company, which may require us to recruit more management personnel.

We will need to increase the size and capabilities of our organization, and we may experience difficulties in managing our growth.

We expect to experience significant growth in the number of our employees and consultants and the scope of our operations, particularly in the areas of clinical development, regulatory affairs and business development. To manage our anticipated future growth, we must continue to implement and improve our managerial, operational and financial systems, expand our facilities and continue to recruit and train additional qualified personnel. Due to our limited financial resources, we may not be able to effectively manage the expansion of our

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operations or recruit and train additional qualified personnel. The expansion of our operations may lead to significant costs and may divert our management and business development resources. Any inability to manage growth could delay the execution of our business plans or disrupt our operations, and have a material adverse effect on our business.

The data and information that we gather in our research and development process could be inaccurate or incomplete, which could harm our business, reputation, financial condition and results of operations.

We collect, aggregate, process, and analyze data and information from our pre-clinical studies, manufacturing technology development programs and clinical programs. We also engage in substantial information gathering following the identification of a promising drug candidate. Because data in the healthcare industry is fragmented in origin, inconsistent in format, and often incomplete, the overall quality of data collected or accessed in the healthcare industry is often subject to challenge, the degree or amount of data which is knowingly or unknowingly absent or omitted can be material, and we often discover data issues and errors when monitoring and auditing the quality of our data. If we make mistakes in the capture, input, or analysis of these data, our ability to advance the development of our drug candidates may be materially harmed and our business, prospects and reputation may suffer.

We also engage in the procurement of regulatory approvals necessary for the development and commercialization of our products under development, for which we manage and submit data to governmental entities. These processes and submissions are governed by complex data processing and validation policies and regulations. Notwithstanding such policies and regulations, interim, top-line or preliminary data from our clinical trials that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures that could result in material changes in the final data, in which case we may be exposed to liability to a customer, court or government agency that concludes that our storage, handling, submission, delivery, or display of health information or other data was wrongful or erroneous. Although we maintain insurance coverage for clinical trials, this coverage may prove to be inadequate or could cease to be available to us on acceptable terms, if at all. Even unsuccessful claims could result in substantial costs and diversion of management time, attention, and resources. A claim brought against us that is uninsured or under-insured could harm our business, financial condition and results of operations.

In addition, we rely on CROs, our partners and other third parties to monitor and manage data for some of our ongoing pre-clinical and clinical programs and control only certain aspects of their activities. If any of our CROs, our partners or other third parties do not perform to our standards in terms of data accuracy or completeness, data from those pre-clinical and clinical trials may be compromised as a result, and our reliance on these parties does not relieve us of our regulatory responsibilities. For a detailed discussion, see “—Risks Related to Our Reliance on Third Parties—As we rely on third parties to conduct our pre-clinical studies and clinical trials, if we lose our relationships with these third parties or if they do not successfully carry out their contractual duties or meet expected deadlines, we may not be able to obtain regulatory approval for or commercialize our drug candidates and our business could be substantially harmed” above.

We may be subject to liability lawsuits arising from our clinical trials.

We currently carry liability insurance covering our clinical trials. Although we maintain such insurance, any claim that may be brought against us could result in a court judgment or settlement in an amount that is not covered, in whole or in part, by our insurance or which is in excess of the limits of our insurance coverage. Our insurance policies also contain various exclusions, and we may be subject to particular liability claims for which we have no coverage. We will have to pay any amount awarded by a court or negotiated in a settlement that exceed our coverage limitations or that are not covered by our insurance, and we may not have, or be able to obtain, sufficient capital to pay such amounts. In addition, if we cannot successfully defend ourselves against such claims, we may incur substantial liabilities and be required to suspend or delay our ongoing clinical trials. Even a successful defense would require significant financial and management resources.

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Regardless of the merits or eventual outcome, liability claims may result in significant negative consequences to our business and prospects, including, but not limited to:

We have limited insurance coverage, and any claims beyond our insurance coverage may result in our incurring substantial costs and a diversion of resources.

We maintain insurance policies that are required under PRC laws and regulations as well as insurance based on our assessment of our operational needs and industry practice. We also maintain liability insurance covering our clinical trials. In line with industry practice in the PRC, we have elected not to maintain certain types of insurances, such as business interruption insurance or key-man insurance. Our insurance coverage may be insufficient to cover any claim for product liability, damage to our fixed assets or employee injuries. Any liability or damage to, or caused by, our facilities or our personnel beyond our insurance coverage may result in our incurring substantial costs and a diversion of resources.

Disruptions in the financial markets and economic conditions could affect our ability to raise capital.

Global economies could suffer dramatic downturns as the result of a deterioration in the credit markets and related financial crisis as well as a variety of other factors including, extreme volatility in security prices, severely diminished liquidity and credit availability, ratings downgrades of certain investments and declining valuations of others. In the past, governments have taken unprecedented actions in an attempt to address and rectify these extreme market and economic conditions by providing liquidity and stability to the financial markets. If these actions are not successful, the return of adverse economic conditions may cause a significant impact on our ability to raise capital, if needed, on a timely basis and on acceptable terms or at all.

In addition, there is considerable uncertainty over the long-term effects of the expansionary monetary and fiscal policies adopted by the central banks and financial authorities of some of the world’s leading economies, including the United States and China. There have been concerns over unrest and terrorist threats in the Middle East, Europe and Africa and over the conflicts involving Ukraine, Syria and North Korea. There have also been concerns on the relationship among China and other Asian countries, which may result in or intensify potential conflicts in relation to territorial disputes or the trade related disputes between the United States and China. In addition, the impact of the decision by the United Kingdom to withdraw from the European Union, commonly referred to as “Brexit”, and the resulting effect on the political and economic future of the U.K. and the European Union is uncertain. Brexit could adversely affect European and worldwide economic and market conditions and could contribute to instability in global financial and foreign exchange markets. It is unclear whether these challenges and uncertainties will be contained or resolved, and what effects they may have on the global political and economic conditions in the long term. It is unclear whether these challenges and uncertainties will be contained or resolved, and what effects they may have on the global political and economic conditions in the long term.

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Our employees, independent contractors, consultants, commercial partners and vendors may engage in misconduct or other improper activities, including non-compliance with regulatory standards and requirements.

We are exposed to the risk of fraud, misconduct or other illegal activities by our employees, independent contractors, consultants, commercial partners and vendors. Misconduct by these parties could include intentional, reckless and negligent conduct that fails to:

For example, our founder, Dr. Jingwu Zhang Zang, was the corresponding author of a research paper prepared by scientists at GSK China’s research center and published in Nature Medicine in 2010. The paper was retracted in 2013 as a result of misrepresentation of certain data for which Dr. Zang admitted his management oversight, accepted the responsibility as the corresponding author and coordinated the retraction of the paper. In addition, Dr. Zang received a warning letter from the FDA in March 1999 relating to the lack of IND approval before the initiation of a clinical research study in human subjects. We cannot assure you that there will not be any inquiries, investigations or other actions against Dr. Zang by any regulatory or government authorities or any negative publicity against Dr. Zang or us regarding these incidents, any of which could distract Dr. Zang and our management’s attention and negatively affect our business and results of operations.

If we obtain approval of any of our drug candidates and begin commercializing those drugs in the PRC, the United States or other applicable jurisdictions, our potential exposure under the laws of such jurisdictions will increase significantly and our costs associated with compliance with such laws are also likely to increase. These laws may impact, among other things, our current activities with principal investigators and research patients, as well as future sales, marketing and education programs. In particular, the promotion, sales and marketing of healthcare items and services, as well as certain business arrangements in the healthcare industry, are subject to extensive laws designed to prevent fraud, kickbacks, self-dealing and other abusive practices. These laws and regulations may restrict or prohibit a wide range of pricing, discounting, marketing and promotion, structuring and commission(s), certain customer incentive programs and other business arrangements generally. Activities subject to these laws also involve the improper use of information obtained in the course of patient recruitment for clinical trials, which could result in regulatory sanctions and cause serious harm to our reputation.

It is not always possible to identify and deter misconduct by employees and other parties, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to comply with these laws or regulations. If any such actions are instituted against us, and we are not successful in defending ourselves or asserting our rights, those actions could have a significant impact on our business, including the imposition of significant fines or other sanctions.

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If we engage in future acquisitions or strategic partnerships, this may increase our capital requirements, dilute the value of your investment in our ADSs, cause us to incur debt or assume contingent liabilities, and subject us to other risks.

We may evaluate various acquisitions and strategic partnerships, including licensing or acquiring complementary products, intellectual property rights, technologies or businesses. Any potential acquisition or strategic partnership may entail numerous risks, including, but not limited to:

In addition, if we undertake acquisitions, we may issue dilutive securities, assume or incur debt obligations, incur large one-time expenses and acquire intangible assets that could result in significant future amortization expense. Moreover, we may not be able to locate suitable acquisition opportunities and this inability could impair our ability to grow or obtain access to technology or products that may be important to the development of our business.

If we fail to comply with applicable anti-bribery laws, our reputation may be harmed and we could be subject to penalties and significant expenses that have a material adverse effect on our business, financial condition and results of operations.

We are subject to anti-bribery laws in China that generally prohibit companies and their intermediaries from making payments to government officials for the purpose of obtaining or retaining business or securing any other improper advantage. In addition, although currently our primary operating business is in China, we are subject to the Foreign Corrupt Practices Act (the “FCPA”). The FCPA generally prohibits us from making improper payments to non-U.S. officials for the purpose of obtaining or retaining business. Although we have policies and procedures designed to ensure that we, our employees and our agents comply with anti-bribery laws, there is no

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assurance that such policies or procedures will prevent our agents, employees and intermediaries from engaging in bribery activities. Failure to comply with anti-bribery laws could disrupt our business and lead to severe criminal and civil penalties, including imprisonment, criminal and civil fines, loss of our export licenses, suspension of our ability to do business with the government, denial of government reimbursement for our products and/or exclusion from participation in government healthcare programs. Other remedial measures could include further changes or enhancements to our procedures, policies, and controls and potential personnel changes and/or disciplinary actions, any of which could have a material adverse effect on our business, financial condition, results of operations and liquidity. We could also be adversely affected by any allegation that we violated such laws.

Any failure to comply with applicable regulations and industry standards or obtain various licenses and permits could harm our reputation and our business, results of operations and prospects.

A number of governmental agencies or industry regulatory bodies in the PRC, the United States and other applicable jurisdictions impose strict rules, regulations and industry standards governing biopharmaceutical research and development activities, which apply to us. Our or our CROs’ failure to comply with such regulations could result in the termination of ongoing research, administrative penalties imposed by regulatory bodies or the disqualification of data for submission to regulatory authorities. This could harm our business, reputation, prospects for future work and results of operations. For example, if we or our CROs were to treat research animals inhumanely or in violation of international standards set out by the Association for Assessment and Accreditation of Laboratory Animal Care, it could revoke any such accreditation and the accuracy of our animal research data could be questioned.

If we or our CROs or other contractors or consultants fail to comply with environmental, health and safety laws and regulations, we could become subject to fines or penalties or incur costs that could have a material adverse effect on the success of our business.

We and third parties, such as our CROs or other contractors or consultants, are subject to numerous environmental, health and safety laws and regulations, including those governing laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. Our operations involve the use of hazardous and flammable materials, including chemicals and radioactive and biological materials. Our operations also produce hazardous waste products. We generally contract with third parties for the disposal of these materials and wastes. We cannot eliminate the risk of contamination or injury from these materials. In the event of contamination or injury resulting from our use of hazardous materials, we could be held liable for any resulting damages, and any liability could exceed our resources. We also could incur significant costs associated with civil or criminal fines and penalties.

Although we maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of or exposure to hazardous materials, this insurance may not provide adequate coverage against potential liabilities. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us in connection with our storage, use or disposal of biological, hazardous or radioactive materials.

In addition, we may be required to incur substantial costs to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research, development or production efforts. Failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions.

If we face allegations of non-compliance with laws and encounter sanctions, our reputation, revenues and liquidity may suffer, and our drug candidates and future drugs could be subject to restrictions or withdrawal from the market.

Any government investigation of alleged violations of laws could require us to expend significant time and resources in response, and could generate negative publicity. Any failure to comply with ongoing regulatory

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requirements may significantly and adversely affect our ability to commercialize and generate revenues from our drugs. If regulatory sanctions are applied or if regulatory approval is withdrawn, the value of our company and our operating results will be adversely affected. Additionally, if we are unable to generate revenues from our product sales, our potential for achieving profitability will be diminished and the capital necessary to fund our operations will be increased.

Our internal computer systems, or those used by our CROs or other contractors or consultants, may fail or suffer security breaches.

Although to our knowledge we have not experienced any material system failure or security breach to date, if such an event were to occur and cause interruptions in our operations, it could result in a material disruption of our development programs and our business operations. For example, the loss of clinical trial data from completed or future clinical trials could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data. Likewise, we partially rely on our third-party research institution collaborators for research and development of our drug candidates and other third parties for the manufacture of our drug candidates and to conduct clinical trials, and similar events relating to their computer systems could also have a material adverse effect on our business.

To the extent that any disruption or security breach were to result in a loss of, or damage to, our data or applications, or inappropriate disclosure of confidential or proprietary information, we could incur liability and the further development and commercialization of our drug candidates could be delayed.

Failure to comply with existing or future laws and regulations related to privacy or data security could lead to government enforcement actions, which could include civil or criminal fines or penalties, private litigation, other liabilities, and/or adverse publicity. Compliance or the failure to comply with such laws could increase the costs of our products and services, could limit their use or adoption, and could otherwise negatively affect our operating results and business.

The regulatory framework for the collection, use, safeguarding, sharing, transfer and other processing of personal information worldwide is rapidly evolving and is likely to remain uncertain for the foreseeable future. Regulatory authorities in virtually every jurisdiction in which we operate have implemented and are considering a number of legislative and regulatory proposals concerning personal data protection.

Regulatory authorities in China have implemented and are considering a number of legislative and regulatory proposals concerning data protection. For example, China’s Cyber Security Law, which became effective in June 2017, created China’s first national-level data protection for “network operators,” which may include all organizations in China that provide services over the internet or another information network. Numerous regulations, guidelines and other measures are expected to be adopted under the umbrella of the Cyber Security Law. Drafts of some of these measures have now been published, including the draft rules on cross-border transfers published by the China Cyberspace Administration in 2017, which may, upon enactment, require security review before transferring human health-related data out of China. In addition, certain industry-specific laws and regulations affect the collection and transfer of personal data in China. For example, the PRC State Council promulgated Regulations on the Administration of Human Genetic Resources (effective in July 2019), which require approval from the Science and Technology Administration Department of the State Council where human genetic resources, or HGR, are involved in any international collaborative project and additional approval for any export or cross-border transfer of the HGR samples or associated data. It is possible that these laws may be interpreted and applied in a manner that is inconsistent with our practices, potentially resulting in confiscation of HGR samples and associated data, administrative fines and criminal liabilities. In addition, the interpretation and application of data protection laws in China and elsewhere are often uncertain and in flux.

In the United States, we are subject to laws and regulations that address privacy, personal information protection and data security at both the federal and state levels. Numerous laws and regulations, including

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security breach notification laws, health information privacy laws, and consumer protection laws, govern the collection, use, disclosure and protection of health-related and other personal information. Given the variability and evolving state of these laws, we face uncertainty as to the exact interpretation of the new requirements, and we may be unsuccessful in implementing all measures required by regulators or courts in their interpretation.

Regulatory authorities in Europe have implemented and are considering a number of legislative and regulatory proposals concerning data protection. For example, the General Data Protection Regulation (EU) 2016/679, or GDPR, which became effective in May 2018, imposes a broad range of strict requirements on companies subject to the GDPR, such as us, including, but not limited to, requirements relating to having legal bases for processing personal information relating to identifiable individuals and transferring such information outside the European Economic Area (including to the United States), providing details to those individuals regarding the processing of their personal information, keeping personal information secure, having data processing agreements with third parties who process personal information, responding to individuals’ requests to exercise their rights in respect of their personal information, reporting security breaches involving personal data to the competent national data protection authority and affected individuals, and recordkeeping. The GDPR substantially increases the penalties to which we could be subject in the event of any non-compliance, including fines of up to 10,000,000 Euros or up to 2% of our total worldwide annual turnover for certain comparatively minor offenses, or up to 20,000,000 Euros or up to 4% of our total worldwide annual turnover for more serious offenses. Given the new law, we face uncertainty as to the exact interpretation of the new requirements, and we may be unsuccessful in implementing all measures required by data protection authorities or courts in interpretation of the new law. National laws of member states of the European Union are in the process of being adapted to the requirements under the GDPR. Because the GDPR specifically gives member states flexibility with respect to certain matters, national laws may partially deviate from the GDPR and impose different obligations from country to country, leading to additional complexity and uncertainty.

We expect that we will continue to face uncertainty as to whether our efforts to comply with evolving obligations under global data protection, privacy and security laws will be sufficient. Any failure or perceived failure by us to comply with applicable laws and regulations could result in reputational damage or proceedings or actions against us by governmental entities, individuals or others. These proceedings or actions could subject us to significant civil or criminal penalties and negative publicity, result in the delayed or halted transfer or confiscation of certain personal information, require us to change our business practices, increase our costs and materially harm our business, prospects, financial condition and results of operations. In addition, our current and future relationships with customers, vendors, pharmaceutical partners and other third parties could be negatively affected by any proceedings or actions against us or current or future data protection obligations imposed on them under applicable law, including the GDPR. In addition, a data breach affecting personal information, including health information, could result in significant legal and financial exposure and reputational damage that could potentially have an adverse effect on our business.

Our operating results for fiscal year 2020, our China operations and our worldwide operations could be adversely affected by the outbreak of and response to the coronavirus or other health crises.

Our business, financial condition and results of operations could be adversely affected by the COVID-19 outbreak. The global outbreak of COVID-19, the disease caused by a novel strain of coronavirus, has created significant business disruption which could materially and adversely affect our business and operations. The outbreak has resulted in governments implementing numerous measures to contain COVID-19, such as travel bans and restrictions, quarantines, shelter-in-place, temporary shutdown of factories, business limitations, or total lock-down orders. These containment measures are subject to change and may be further tightened. This outbreak has led to temporary closure of our offices in the first quarter of 2020, causing cancellation of physical participation in meetings, restrictions on employee travels, and a significant portion of our employees working from home, which resulted in lower work efficiency and productivity, and the disruption to our business operations and clinical trials.

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The outbreak of COVID-19 and the resulting government measures may materially and adversely impact our planned and ongoing clinical trials and development. Clinical site initiation, including recruiting clinical site investigators and clinical site staff, and patient enrollment may be delayed due to prioritization of hospital resources toward the COVID-19 pandemic. The diversion of healthcare resources away from the conduct of clinical trials to focus on pandemic concerns, including the attention of physicians serving as our clinical trial investigators and hospitals serving as our clinical trial sites, or other staff supporting the conduct of our clinical trials may significantly disrupt our research activities. Hospitals have also had reduced patient flow in general during the outbreak period. As a result, the expected timeline for data readouts of our clinical trials and potential submission and filings will likely be negatively impacted, which would adversely affect and delay our ability to obtain certain regulatory approvals, increase our operating expenses and have a material adverse effect on our financial condition. Furthermore, we could face the interruption of key clinical activities such as trial site data monitoring, which may impact the integrity of clinical data. Similarly, our ability to recruit and retain patients and principal investigators and site staff who, as healthcare providers, may have heightened exposure to COVID-19, may be impeded, which would also materially and adversely impact our clinical trial operations. As a result of disruptions caused by the COVID-19 pandemic, we may require additional capital to continue our research activities, which we may be unable to secure on favorable terms, if at all. In addition, we believe that our business partners, such as our licensing partners, CROs, CMOs or suppliers, have also experienced and may continue to experience similar or more severe disruptions to their business operations. Any disruption to the business operations of us and our business partners could materially and adversely affect the development of our drug candidates, our business, financial condition and results of operations. To the extent the COVID-19 pandemic adversely affects our business and financial results, it may also have the effect of heightening many of the other risks described in this “Risk Factors” section. See also “Management’s Discussion And Analysis Of Financial Condition And Results Of Operations––Impact of the COVID-19 Outbreak on Our Business” for a detailed description of the impact of the COVID-19 outbreak on our business.

Business disruptions could seriously harm our future revenue and financial condition and increase our costs and expenses.

Natural disasters, acts of war or terrorism, health epidemics, or other factors beyond our control may adversely affect the economy, infrastructure and livelihood of the people in the regions where we conduct our business. Our operations may be under the threat of floods, earthquakes, sandstorms, snowstorms, fire or drought, power, water or fuel shortages, failures, malfunction and breakdown of information management systems, unexpected maintenance or technical problems, or may be susceptible to potential wars or terrorist attacks. Serious natural disasters may result in loss of lives, injury, destruction of assets and disruption of our business and operations. Acts of war or terrorism may also injure our employees, cause loss of lives, disrupt our business network and destroy our markets. Any of these factors and other factors beyond our control could have an adverse effect on the overall business sentiment and environment, cause uncertainties in the regions where we conduct business, cause our business to suffer in ways that we cannot predict and materially and adversely impact our business, financial conditions and results of operations.

Our business and results of operations could be adversely affected by public health crisis (including the COVID-19 global pandemic) and natural catastrophes or other disasters outside of our control in the locations in which we, our suppliers, CROs, CMOs and other contractors operate.

Our business could be adversely affected by the effects of epidemics, including COVID-19, avian influenza, severe acute respiratory syndrome, (SARS), influenza A (H1N1), Ebola or another epidemic. Any such occurrences could cause severe disruption to our daily operations and may even require a temporary closure of our offices and laboratories. For example, in early 2020, in response to intensifying efforts to contain the spread of COVID-19, the Chinese government took a number of actions, which included extending the Chinese New Year holiday, quarantining individuals infected with or suspected of having COVID-19, prohibiting residents from free travel, encouraging employees of enterprises to work remotely from home and cancelling public activities, among others. The COVID-19 pandemic has also resulted in temporary closure of many corporate

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offices, retail stores, manufacturing facilities and factories. As research hospitals and government agencies focus clinical resources on the pandemic, we believe that there could be some delay in regulatory interactions and inspections and patient recruitment and participation, particularly in the first quarter of 2020. Meanwhile, the outbreak of COVID-19 continues in the United States and other countries, and related government and private sector responsive actions may cause some delay in our ongoing clinical trials in the United States. We have taken a series of measures in response to the outbreak, including, among others, remote working arrangement for our employees. These measures could reduce the capacity and efficiency of our operations, which in turn could negatively affect our results of operations. The extent to which COVID-19 impacts our results of operations will depend on the future developments of the outbreak, including new information concerning the global severity of and actions taken to contain the outbreak, which are highly uncertain and unpredictable. These uncertain and unpredictable factors include, but are not limited to, potential adverse effects of the pandemic on the economy, our suppliers, CROs, CMOs and other contractors. In addition, our results of operations could be adversely affected to the extent that the outbreak harms the Chinese economy in general. To the extent the COVID-19 pandemic adversely affects our business and financial results, it may also have the effect of heightening many of the other risks described in this prospectus supplement, including those relating to our ability to initiate or continue clinical trials for our drug candidates.

We have identified two material weaknesses in our internal controls, and if we fail to implement and maintain an effective system of internal controls to remediate our material weaknesses over financial reporting, we may be unable to accurately report our results of operations, meet our reporting obligations or prevent fraud.

Prior to the initial public offering of our ADSs on NASDAQ in January 2020, we were a private company with limited accounting personnel and other resources with which to address our internal controls and procedures. Effective internal control over financial reporting is necessary for us to provide reliable financial reports and, together with adequate disclosure controls and procedures, are designed to prevent fraud. In the course of auditing our consolidated financial statements as of and for the year ended December 31, 2019, we and our independent registered public accounting firm identified two material weaknesses and control deficiencies in our internal control over financial reporting. As defined in the standards established by the U.S. Public Company Accounting Oversight Board, a “material weakness” is a deficiency, or combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of the company’s annual or interim financial statements will not be prevented or detected on a timely basis.

The material weaknesses that have been identified relate to (i) our lack of sufficient and competent financial reporting and accounting personnel with appropriate knowledge of U.S. GAAP and the reporting and compliance requirements of the United States Securities and Exchange Commission, or the SEC, to formalize key controls over financial reporting and to prepare consolidated financial statements and related disclosures; and (ii) our lack of sufficient documented financial closing policies and procedures, specifically those related to (a) accounting for licensing and collaboration agreements and (b) period end expenses cut-off and accruals. These material weaknesses, if not timely remedied, may lead to significant misstatements in our consolidated financial statements in the future. Following the identification of the material weaknesses and other control deficiencies, we have taken measures and plan to continue to take measures to remediate these deficiencies. However, the implementation of those measures may not fully remediate the material weaknesses in a timely manner. Our failure to correct these deficiencies or our failure to discover and address any other deficiencies could result in inaccuracies in our financial statements and impair our ability to comply with applicable financial reporting requirements and related regulatory filings on a timely basis. Moreover, ineffective internal control over financial reporting could significantly hinder our ability to prevent fraud.

As required by Section 404 of the Sarbanes-Oxley Act, or Section 404, we will include a report from management on the effectiveness of our internal control over financial reporting in our annual report on Form 20-F beginning with our annual report for the fiscal year ending December 31, 2020. In addition, once we cease to be an “emerging growth company” as defined in the JOBS Act, our independent registered public accounting firm must attest to and report on the effectiveness of our internal control over financial reporting. Our

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management may conclude that our internal control over financial reporting is not effective. Moreover, even if our management concludes that our internal control over financial reporting is effective, our independent registered public accounting firm, after conducting its own independent testing, may issue an adverse report if it is not satisfied with our internal controls or the level at which our controls are documented, designed, operated or reviewed, or if it interprets the relevant requirements differently from us. In addition, as a public company, our reporting obligations may place a significant strain on our management, operational and financial resources and systems for the foreseeable future. We may be unable to timely complete our evaluation testing and any required remediation.

During the course of documenting and testing our internal control procedures, in order to satisfy the requirements of Section 404, we may identify other weaknesses and deficiencies in our internal control over financial reporting. In addition, if we fail to maintain the adequacy of our internal control over financial reporting, as these standards are modified, supplemented or amended from time to time, we may not be able to conclude on an ongoing basis that we have effective internal control over financial reporting in accordance with Section 404. If we fail to establish and maintain adequate internal controls, we could suffer material misstatements in our financial statements and fail to meet our reporting obligations, which would likely cause investors to lose confidence in our reported financial information. This could limit our access to capital markets, adversely affect our results of operations and lead to a decline in the trading price of the ADSs. Additionally, ineffective internal controls could expose us to an increased risk of fraud or misuse of corporate assets and subject us to potential delisting from the stock exchange on which we list or to other regulatory investigations and civil or criminal sanctions. We could also be required to restate our historical financial statements.

Our auditor, like other independent registered public accounting firms operating in China, is not permitted to be subject to inspection by Public Company Accounting Oversight Board, and consequently investors may be deprived of the benefits of such inspection. In addition, the adoption of any rules, legislations or other efforts to increase U.S. regulatory access to audit information could cause uncertainty and we could be delisted if we are unable to meet the PCAOB inspection requirement in time.

Our auditor, the independent registered public accounting firm that issued the audit report included in our annual report on Form 20-F filed with the SEC on April 29, 2020, which is incorporated into the accompanying prospectus by reference, as an auditor of companies that are traded publicly in the United States and a firm registered with the Public Company Accounting Oversight Board (United States), or PCAOB, is subject to laws in the United States pursuant to which the PCAOB conducts regular inspections to assess its compliance with applicable professional standards. Our auditor is located in, and organized under the laws of, the PRC, which is a jurisdiction where the PCAOB, has been unable to conduct inspections without the approval of the Chinese authorities. In May 2013, PCAOB announced that it had entered into a Memorandum of Understanding on Enforcement Cooperation with the CSRC and the PRC Ministry of Finance, which establishes a cooperative framework between the parties for the production and exchange of audit documents relevant to investigations undertaken by PCAOB, the CSRC or the PRC Ministry of Finance in the United States and the PRC, respectively. PCAOB continues to be in discussions with the China Securities Regulatory Commission, or CSRC, and the PRC Ministry of Finance to permit joint inspections in China of audit firms that are registered with PCAOB and audit Chinese companies that trade on U.S. exchanges.

On December 7, 2018, the SEC and the PCAOB issued a joint statement highlighting continued challenges faced by the U.S. regulators in their oversight of financial statement audits of U.S.-listed companies with significant operations in China. The joint statement reflects a heightened interest in an issue that has vexed U.S. regulators in recent years.

On April 21, 2020, the SEC and the PCAOB issued another joint statement reiterating the greater risk that disclosures will be insufficient in many emerging markets, including China, compared to those made by U.S. domestic companies. In discussing the specific issues related to the greater risk, the statement again highlights the PCAOB’s inability to inspect audit work paper and practices of accounting firms in China, with respect to

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their audit work of U.S. reporting companies. However, it remains unclear what further actions the SEC and PCAOB will take to address the problem.

On June 4, 2020, the U.S. President issued a memorandum ordering the President’s Working Group on Financial Markets, or the PWG, to submit a report to the President within 60 days of the memorandum that includes recommendations for actions that can be taken by the executive branch and by the SEC or PCAOB on Chinese companies listed on U.S. stock exchanges and their audit firms, in an effort to protect investors in the United States.

On August 6, 2020, the PWG released a report recommending that the SEC take steps to implement the five recommendations outlined in the report. In particular, to address companies from jurisdictions that do not provide the PCAOB with sufficient access to fulfill its statutory mandate, or NCJs, the PWG recommends enhanced listing standards on U.S. stock exchanges. This would require, as a condition to initial and continued exchange listing, PCAOB access to work papers of the principal audit firm for the audit of the listed company. Companies unable to satisfy this standard as a result of governmental restrictions on access to audit work papers and practices in NCJs may satisfy this standard by providing a co-audit from an audit firm with comparable resources and experience where the PCAOB determines it has sufficient access to audit work papers and practices to conduct an appropriate inspection of the co-audit firm. The report permits the new listing standards to provide for a transition period until January 1, 2022 for listed companies, but would apply immediately to new listings once the necessary rulemakings and/or standard-setting are effective. If we fail to meet the new listing standards before the deadline specified thereunder due to factors beyond our control, we could face possible de-listing from the Nasdaq Global Market, deregistration from the SEC and/or other risks, which may materially and adversely affect the market price and liquidity of our ADS, or effectively terminate our ADS trading in the United States. There were recent media reports about the SEC’s proposed rulemaking in this regard. It is uncertain whether the PWG recommendations will be adopted, in whole or in part, and the impact of any new rule on us cannot be estimated at this time.

This lack of PCAOB inspections in China prevents the PCAOB from fully evaluating audits and quality control procedures of our independent registered public accounting firm. As a result, we and investors in our ordinary shares are deprived of the benefits of such PCAOB inspections. The inability of the PCAOB to conduct inspections of auditors in China makes it more difficult to evaluate the effectiveness of our independent registered public accounting firm’s audit procedures or quality control procedures as compared to auditors outside of China that are subject to PCAOB inspections, which could cause investors and potential investors in our stock to lose confidence in our audit procedures and reported financial information and the quality of our financial statements.

On December 7, 2018, the SEC and the PCAOB issued a joint statement highlighting continued challenges faced by the U.S. regulators in their oversight of financial statement audits of U.S.-listed companies with significant operations in China. As part of a continued regulatory focus in the United States on access to audit and other information currently protected by national law, in particular the PRC’s, in June 2019, a bipartisan group of lawmakers introduced bills in both houses of the U.S. Congress that would require the SEC to maintain a list of issuers for which PCAOB is not able to inspect or investigate an auditor report issued by a foreign public accounting firm. The Ensuring Quality Information and Transparency for Abroad-Based Listings on our Exchanges (EQUITABLE) Act prescribes increased disclosure requirements for these issuers and, beginning in 2025, the delisting from U.S. national securities exchanges such as Nasdaq of issuers included on the SEC’s list for three consecutive years. On December 18, 2020, the Holding Foreign Companies Accountable Act, or the HFCA Act, was enacted into law, which requires the SEC to prohibit any foreign company from listing securities on U.S. securities exchanges if such company retains a foreign accounting firm that cannot be inspected by the PCAOB for three consecutive years, beginning in 2021. The enactment of the HFCA Act and any additional rulemaking efforts to increase U.S. regulatory access to audit information in China may prohibit our securities from trading on Nasdaq or other U.S. stock exchanges if our auditor is not inspected by the PCAOB for three consecutive years, and this ultimately could result in our ADSs being delisted. While we understand that there

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has been dialogue among the CSRC, the SEC and the PCAOB regarding the inspection of PCAOB-registered accounting firms in China, there can be no assurance that our auditor or us will be able to comply with requirements imposed by U.S. regulators. Delisting of our ADSs would force our U.S.-based shareholders to sell their ADSs or convert them into Class A ordinary shares listed in Hong Kong. Although we are listed in Hong Kong, investors may face difficulties in migrating their underlying ordinary shares to Hong Kong, or may have to incur increased costs or suffer losses in order to do so. The market prices of our ADSs could be adversely affected as a result of anticipated negative impacts of the HFCA Act upon, as well as negative investor sentiment towards, China-based companies listed in the United States, regardless of whether the HFCA Act is enacted and regardless of our actual operating performance. In addition, on June 4, 2020, the U.S. President issued a memorandum ordering the President’s Working Group on Financial Markets, or the PWG, to submit a report to the President within 60 days of the memorandum that includes recommendations for actions that can be taken by the executive branch and by the SEC or PCAOB on Chinese companies listed on U.S. stock exchanges and their audit firms, in an effort to protect investors in the U.S. On August 6, 2020, the PWG released a report recommending that the SEC take steps to implement the five recommendations outlined in the report. In particular, to address companies from jurisdictions that do not provide the PCAOB with sufficient access to fulfill its statutory mandate, or NCJs, the PWG recommends enhanced listing standards on U.S. stock exchanges. This would require, as a condition to initial and continued exchange listing, PCAOB access to work papers of the principal audit firm for the audit of the listed company. Companies unable to satisfy this standard as a result of governmental restrictions on access to audit work papers and practices in NCJs may satisfy this standard by providing a co-audit from an audit firm with comparable resources and experience where the PCAOB determines it has sufficient access to audit work papers and practices to conduct an appropriate inspection of the co-audit firm. The report permits the new listing standards to provide for a transition period until January 1, 2022 for listed companies, but would apply immediately to new listings once the necessary rulemakings and/or standard-setting are effective. Any resulting actions, proceedings or new rules could adversely affect the listing and compliance status of China-based issuers listed in the United States, such as our company, and may have a material and adverse impact on the trading prices of the securities of such issuers, including our ADSs and potentially our Class A ordinary shares, and substantially reduce or effectively terminate the trading of our ADSs in the United States.

Proceedings instituted by the SEC against “big four” PRC-based accounting firms, including our independent registered public accounting firm, could result in financial statements being determined to not be in compliance with the requirements of the Exchange Act.

Starting in 2011 “big four” PRC-based accounting firms, including our independent registered public accounting firm, were affected by a conflict between U.S. and Chinese law. Specifically, for certain U.S.-listed companies operating and audited in mainland China, the SEC and the PCAOB sought to obtain from the Chinese firms access to their audit work papers and related documents. The firms were, however, advised and directed that under Chinese law, they could not respond directly to the U.S. regulators on those requests, and that requests by foreign regulators for access to such papers in China had to be channeled through the CSRC.

In late 2012, this impasse led the SEC to commence administrative proceedings under Rule 102(e) of its Rules of Practice and also under the Sarbanes-Oxley Act of 2002 against the Chinese accounting firms, including our independent registered public accounting firm. A first instance trial of the proceedings in July 2013 in the SEC’s internal administrative court resulted in an adverse judgment against the firms. The administrative law judge proposed penalties on the firms including a temporary suspension of their right to practice before the SEC, although that proposed penalty did not take effect pending review by the Commissioners of the SEC. On February 6, 2015, before a review by the Commissioner had taken place, the firms reached a settlement with the SEC. Under the settlement, the SEC accepted that future requests by the SEC for the production of documents will normally be made to the CSRC. The firms were to receive matching Section 106 requests, and were required to abide by a detailed set of procedures with respect to such requests, which in substance require them to facilitate production via the CSRC. If they failed to meet specified criteria, the SEC retained authority to impose a variety of additional remedial measures on the firms depending on the nature of the failure.

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Under the terms of the settlement, the underlying proceeding against the four China-based accounting firms was deemed dismissed with prejudice four years after entry of the settlement. The four-year mark occurred on February 6, 2019. While we cannot predict if the SEC will further challenge the four China-based accounting firms’ compliance with U.S. law in connection with U.S. regulatory requests for audit work papers or if the results of such a challenge would result in the SEC imposing penalties such as suspensions. If additional remedial measures are imposed on the “big four” PRC-based accounting firms, including our independent registered public accounting firm, we could be unable to timely file future financial statements in compliance with the requirements of the Exchange Act.

In the event the “big four” PRC-based accounting firms become subject to additional legal challenges by the SEC or PCAOB, depending upon the final outcome, listed companies in the United States with major PRC operations may find it difficult or impossible to retain auditors in respect of their operations in China, which could result in financial statements being determined to not be in compliance with the requirements of the Exchange Act, including possible delisting. Moreover, any negative news about any such future proceedings against these audit firms may cause investor uncertainty regarding China-based, U.S.-listed companies and the market price of our common stock may be adversely affected.

If our independent registered public accounting firm was denied, even temporarily, the ability to practice before the SEC and we were unable to timely find another registered public accounting firm to audit and issue an opinion on our financial statements, our financial statements could be determined not to be in compliance with the requirements of the Exchange Act. Such a determination could ultimately lead to the delisting of the ADSs from the Nasdaq Global Market or deregistration from the SEC, or both, which would substantially reduce or effectively terminate the trading of the ADSs in the United States.

Our reputation is important to our business success. Negative publicity may adversely affect our reputation and business prospects.

Any negative publicity concerning us, our affiliates or any entity that shares the “I-Mab” name, even if untrue, could adversely affect our reputation and business prospects. There can be no assurance that negative publicity about us or any of our affiliates or any entity that shares the “I-Mab” name would not damage our brand image or have a material adverse effect on our business, results of operations and financial condition.

We may be subject to material litigation and regulatory proceedings.

We may be subject to litigation in China and outside China relating to securities law class actions, third-party and principal intellectual property infringement claims, claims relating to data and privacy protection, employment related cases and other matters in the ordinary course of our business. Laws, rules and regulations may vary in their scope and overseas laws and regulations may impose requirements that are more stringent than, or which conflict with, those in China. We have acquired and may acquire companies that may become subject to litigation, as well as regulatory proceedings. In addition, in connection with litigation or regulatory proceedings we may be subject to in various jurisdictions, we may be prohibited by laws, regulations or government authorities in one jurisdiction from complying with subpoenas, orders or other requests from courts or regulators of other jurisdictions, including those relating to data held in or with respect to persons in these jurisdictions. Our failure or inability to comply with the subpoenas, orders or requests could subject us to fines, penalties or other legal liability, which could have a material adverse effect on our reputation, business, results of operations and the trading price of our ADSs.

As a publicly-listed company, we and certain of our subsidiaries face additional exposure to claims and lawsuits inside and outside China. We will need to defend against these lawsuits, including any appeals should our initial defense be successful. The litigation process may utilize a material portion of our cash resources and divert management’s attention away from the day-to-day operations of our company, all of which could harm our business. There can be no assurance that we will prevail in any of these cases, and any adverse outcome of these

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cases could have a material adverse effect on our reputation, business and results of operations. In addition, although we have obtained directors’ and officers’ liability insurance, the insurance coverage may not be adequate to cover our obligations to indemnify our directors and officers, fund a settlement of litigation in excess of insurance coverage or pay an adverse judgment in litigation.

The existence of litigation, claims, investigations and proceedings may harm our reputation, limit our ability to conduct our business in the affected areas and adversely affect the trading price of our ADSs. The outcome of any claims, investigations and proceedings is inherently uncertain, and in any event defending against these claims could be both costly and time-consuming, and could significantly divert the efforts and resources of our management and other personnel. An adverse determination in any litigation, investigation or proceeding could cause us to pay damages, incur legal and other costs, limit our ability to conduct business or require us to change the manner in which we operate.

Negative publicity with respect to us, our management, employees, business partners, affiliates, or our industry, may materially and adversely affect our reputation, business, results of operations and prospect.

Our reputation is vulnerable to many threats that can be difficult or impossible to control, and costly or impossible to remediate. Negative publicity about us, such as alleged misconduct or improper activities, or negative rumors relating to us, our management, employees, business partners or affiliates, can harm our business and results of operations, even if they are unsubstantiated or are satisfactorily addressed. For example, a number of media reported that our founder, Dr. Jingwu Zhang Zang, was involved in misrepresentation of certain data in a research paper prepared by scientists at GSK China’s research center and published in Nature Medicine in 2010, for which Dr. Zang was the corresponding author, and consequently Dr. Zang was dismissed by GSK in 2013. In addition, Dr. Zang received a warning letter from the FDA in March 1999 relating to the lack of IND approval before the initiation of a clinical research study in human subjects. To the best of our knowledge, Dr. Zang was not and is not subject to any legal or regulatory charges, proceedings or disciplinary actions in connection with these incidents or by relevant parties involved in the incidents. However, we cannot assure you that there will not be any inquiries, investigations or other actions against Dr. Zang by any regulatory or government authorities in the future. Any regulatory inquiries or investigations or other actions against our management, any perceived unethical, fraudulent, or inappropriate business conduct by us or perceived wrong doing by any key member of our management team or other employees, our business partners or our affiliates, could harm our reputation and materially adversely affect our business. Regardless of the merits or final outcome of any such regulatory inquiries or investigations or other actions, our reputation may be substantially damaged, which may impede our ability to attract and retain talents and business partners and grow our business.

Moreover, any negative media publicity about the biopharmaceutical industry in general or product or service quality problems of other companies in the industry, including our peers, may also negatively impact our reputation. If we are unable to maintain a good reputation, our ability to attract and retain key employees and business partners could be harmed which in turn may materially and adversely affect our business, results of operations and prospect.

Change in business prospects of acquisitions may result in impairment to our goodwill, which could negatively affect our reported results of operations.

We acquired a controlling interest in I-Mab Tianjin in July 2017 and the remaining interest in I-Mab Tianjin in May 2018. In connection with our acquisition of I-Mab Tianjin, we identified RMB148.8 million of intangible assets and RMB162.6 million of goodwill of I-Mab Tianjin attributable to core technology and synergy effects expected from combining the operations of the discovery and development of innovative biologics and the development of clinical stage biologics. We are required to test our goodwill annually, or more frequently if events or changes in circumstances indicate that it might be impaired. Goodwill is allocated to cash-generating units or groups of cash-generating units for the purpose of impairment testing. An impairment loss of goodwill is recognized for the amount by which the relevant cash-generating unit’s or group of cash-generating unit’s

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carrying amount exceeds its recoverable amount, and we would be required to write down the carrying value of our goodwill during the period in which it is determined to be impaired, which would materially and adversely affect our results of operations.

We are subject to changing law and regulations regarding regulatory matters, corporate governance and public disclosure that have increased both our costs and the risk of non-compliance.

We are or will be subject to rules and regulations by various governing bodies, including, for example, the SEC, which is charged with the protection of investors and the oversight of companies whose securities are publicly traded, and the various regulatory authorities in China and the Cayman Islands, and to new and evolving regulatory measures under applicable law. Our efforts to comply with new and changing laws and regulations have resulted in and are likely to continue to result in, increased general and administrative expenses and a diversion of management time and attention from revenue-generating activities to compliance activities.

Moreover, because these laws, regulations and standards are subject to varying interpretations, their application in practice may evolve over time as new guidance becomes available. This evolution may result in continuing uncertainty regarding compliance matters and additional costs necessitated by ongoing revisions to our disclosure and governance practices. If we fail to address and comply with these regulations and any subsequent changes, we may be subject to penalty and our business may be harmed.

Risks Related to Doing Business in China

The pharmaceutical industry in China is highly regulated and such regulations are subject to change which may affect approval and commercialization of our drugs.

Our research and development operations and manufacturing facilities are in China, which we believe confers clinical, commercial and regulatory advantages. The pharmaceutical industry in China is subject to comprehensive government regulation and supervision, encompassing the approval, registration, manufacturing, packaging, licensing and marketing of new drugs. In recent years, the regulatory framework in China regarding the pharmaceutical industry has undergone significant changes, and we expect that it will continue to undergo significant changes. Any such changes or amendments may result in increased compliance costs on our business or cause delays in or prevent the successful development or commercialization of our drug candidates in China and reduce the current benefits we believe are available to us from developing and manufacturing drugs in China. PRC authorities have become increasingly vigilant in enforcing laws in the pharmaceutical industry and any failure by us or our partners to maintain compliance with applicable laws and regulations or obtain and maintain required licenses and permits may result in the suspension or termination of our business activities in China. We believe our strategy and approach are aligned with the PRC government’s regulatory policies, but we cannot ensure that our strategy and approach will continue to be aligned.

Changes in the political and economic policies of the PRC government may materially and adversely affect our business, financial condition and results of operations and may result in our inability to sustain our growth and expansion strategies.

A significant portion of our operations are in China. Our financial condition and results of operations are affected to a large extent by economic, political and legal developments in China.

The PRC economy differs from the economies of most developed countries in many respects, including the extent of government involvement, level of development, growth rate, control of foreign exchange and allocation of resources. Although the PRC government has implemented measures emphasizing the utilization of market forces for economic reform, the reduction of state ownership of productive assets, and the establishment of improved corporate governance in business enterprises, a substantial portion of productive assets in China is still owned by the government. In addition, the PRC government continues to play a significant role in regulating

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industrial development by imposing industrial policies. The PRC government also exercises significant control over China’s economic growth by allocating resources, controlling payment of foreign currency-denominated obligations, setting monetary policy, regulating financial services and institutions and providing preferential treatment to particular industries or companies.

While the PRC economy has experienced significant growth in the past four decades, growth has been uneven, both geographically and among various sectors of the economy. The PRC government has implemented various measures to encourage economic growth and guide the allocation of resources. Some of these measures may benefit the overall PRC economy, but may also have a negative effect on us. Our business, financial condition and results of operations could be materially and adversely affected by government control over capital investments or changes in tax regulations that are applicable to us.

In addition, the PRC government had, in the past, implemented certain measures, including interest rate increases, to control the pace of economic growth. These measures may cause decreased economic activity in China, which may adversely affect our business and results of operations. More generally, if the business environment in China deteriorates from the perspective of domestic or international investment, our business in China may also be adversely affected.

There are uncertainties regarding the interpretation and enforcement of PRC laws, rules and regulations.

Our primary business is governed by PRC laws and regulations. Our primary business operation is supervised by relevant regulatory authorities in China. The PRC legal system is a civil law system based on written statutes and, unlike the common law system, prior court decisions can only be cited as reference and have limited precedential value. Additionally, written statutes in the PRC are often principle-oriented and require detailed interpretations by the enforcement bodies to further apply and enforce such laws. Since 1979, the PRC government has developed a comprehensive system of laws, rules and regulations in relation to economic matters, such as foreign investment, corporate organization and governance, commerce, taxation and trade. However, the interpretation and enforcement of these laws, rules and regulations involve uncertainties and may not be as consistent or predictable as in other more developed jurisdictions. As these laws and regulations are continually evolving in response to changing economic and other conditions, and because of the limited volume of published cases and their non-binding nature, any particular interpretation of PRC laws and regulations may not be definitive. Moreover, we cannot predict the effect of future developments in the PRC legal system and regulatory structure. Such unpredictability towards our contractual, property and procedural rights as well as our rights licensed, approved or granted by the competent regulatory authority could adversely affect our business and impede our ability to continue our operations. In addition, the PRC legal system is based in part on government policies and internal rules, some of which are not published on a timely basis, if at all, and which may have a retroactive effect. Hence, we may not be aware of violation of these policies and rules until after such violation has occurred. Further, the legal protections available to us and our investors under these laws, rules and regulations may be limited.

In addition, any administrative or court proceedings in China may be protracted, resulting in substantial costs and diversion of resources and management attention. Since PRC administrative and court authorities have significant discretion in interpreting and implementing statutory and contractual terms, it may be more difficult to evaluate the outcome of administrative and court proceedings and the level of legal protection we enjoy than in more developed legal systems. These uncertainties may impede our ability to enforce various contracts we have entered into and could materially and adversely affect our business, financial condition and results of operations.

You may experience difficulties in effecting service of legal process, enforcing foreign judgments or bringing actions in China against us or our management named in the prospectus based on foreign laws.

We are a company incorporated under the laws of the Cayman Islands, we conduct substantially all of our operations in China and substantially all of our assets are located in China. In addition, all our senior executive

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officers reside within China for a significant portion of the time and some of them are PRC nationals. As a result, it may be difficult for you to effect service of process upon us or those persons inside China. It may also be difficult for you to enforce in U.S. courts judgments obtained in U.S. courts based on the civil liability provisions of the U.S. federal securities laws against us and our officers and directors as none of them currently resides in the United States or has substantial assets located in the United States. In addition, there is uncertainty as to whether the courts of the Cayman Islands or the PRC would recognize or enforce judgments of U.S. courts against us or such persons predicated upon the civil liability provisions of the securities laws of the United States or any state.

The recognition and enforcement of foreign judgments are provided for under the PRC Civil Procedures Law. PRC courts may recognize and enforce foreign judgments in accordance with the requirements of the PRC Civil Procedures Law based either on treaties between China and the country where the judgment is made or on principles of reciprocity between jurisdictions. China does not have any treaties or other forms of written arrangement with the United States that provide for the reciprocal recognition and enforcement of foreign judgments. In addition, according to the PRC Civil Procedures Law, the PRC courts will not enforce a foreign judgment against us or our directors and officers if they decide that the judgment violates the basic principles of PRC laws or national sovereignty, security or the public interest. As a result, it is uncertain whether and on what basis a PRC court would enforce a judgment rendered by a court in the United States.

It may be difficult for overseas regulators to conduct investigation or collect evidence within China.

Shareholder claims or regulatory investigation that are common in the United States generally are difficult to pursue as a matter of law or practicality in China. For example, in China, there are significant legal and other obstacles to providing information needed for regulatory investigations or litigations initiated outside China. Although the authorities in China may establish a regulatory cooperation mechanism with the securities regulatory authorities of another country or region to implement cross-border supervision and administration, such cooperation with the securities regulatory authorities in the Unities States may not be efficient in the absence of mutual and practical cooperation mechanism. Furthermore, according to Article 177 of the PRC Securities Law, which became effective in March 2020, no overseas securities regulator is allowed to directly conduct investigation or evidence collection activities within the PRC territory. While detailed interpretation of or implementation rules under Article 177 have yet to be promulgated, the inability for an overseas securities regulator to directly conduct investigation or evidence collection activities within China may further increase the difficulties you face in protecting your interests. See also “—Risks Related to Our ADSs and This Offering—You may face difficulties in protecting your interests, and your ability to protect your rights through U.S. courts may be limited, because we are incorporated under Cayman Islands law.” for risks associated with investing in us as a Cayman Islands company.

We may be restricted from transferring our scientific data abroad.

On March 17, 2018, the General Office of the PRC State Council promulgated the Measures for the Management of Scientific Data, or the Scientific Data Measures, which provide a broad definition of scientific data and relevant rules for the management of scientific data. According to the Scientific Data Measures, enterprises in China must seek governmental approval before any scientific data involving a state secret may be transferred abroad or to foreign parties. Further, any researcher conducting research funded, at least in part, by the PRC government is required to submit relevant scientific data for management by the entity to which such researcher is affiliated before such data may be published in any foreign academic journal. Currently, as the term “state secret” is not clearly defined, there is no assurance that we can always obtain relevant approvals for sending scientific data (such as the results of our pre-clinical studies or clinical trials conducted within China) abroad, or to our foreign partners in China.

If we are unable to obtain the necessary approvals in a timely manner, or at all, our research and development of drug candidates may be hindered, which may materially and adversely affect our business,

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results of operations, financial conditions and prospects. If relevant government authorities consider the transmission of our scientific data to be in violation of the requirements under the Scientific Data Measures, we may be subject to specific administrative penalties imposed by those government authorities.

Changes in international trade policies and rising political tensions, particularly between the U.S. and China, may adversely impact our business and operating results.

The U.S. government has made statements and taken certain actions that may lead to potential changes to U.S. and international trade policies towards China. While the “Phase One” agreement was signed between the United States and China on trade matters, it remains unclear what additional actions, if any, will be taken by the U.S. or other governments with respect to international trade, tax policy related to international commerce, or other trade matters. The situation is further complicated by the political tensions between the United States and China that escalated during the COVID-19 pandemic and in the wake of the PRC National People’s Congress’ decision on Hong Kong national security legislation, sanctions imposed by the U.S. Department of Treasury on certain officials of the Hong Kong Special Administrative Region and the central government of the PRC and the executive orders issued by U.S. President in August 2020 that prohibit certain transactions with certain China-based companies and their respective subsidiaries. Rising trade and political tensions could reduce levels of trades, investments, technological exchanges and other economic activities between China and other countries, which would have an adverse effect on global economic conditions, the stability of global financial markets, and international trade policies.

While we have not started commercialization of drug candidates, any rising trade and political tensions or unfavorable government policies on international trade, such as capital controls or tariffs, may affect the demand for our drug products, the competitive position of our drug products, the hiring of scientists and other research and development personnel, and import or export of raw materials in relation to drug development, or prevent us from selling our drug products in certain countries. In particular, if any new tariffs, legislation and/or regulations are implemented, or if existing trade agreements are renegotiated or, especially, if the U.S. government takes retaliatory trade actions due to the recent U.S.-China trade and political tension, such changes could have an adverse effect on our business, financial condition and results of operations. In addition, our results of operations could be adversely affected if any such tensions or unfavorable government trade policies harm the Chinese economy or the global economy in general.

If we are classified as a PRC resident enterprise for PRC income tax purposes, such classification could result in unfavorable tax consequences to us and our non-PRC shareholders or ADS holders.

Under the PRC Enterprise Income Tax Law and its implementation rules, an enterprise established outside of the PRC with “de facto management body” within China is considered a “resident enterprise” and will be subject to the enterprise income tax on its global income at the rate of 25%. The implementation rules define the term “de facto management body” as the body that exercises full and substantial control and overall management over the business, productions, personnel, accounts and properties of an enterprise. In 2009, the SAT issued the Circular of the State Administration of Taxation on Issues Relating to Identification of PRC-Controlled Overseas Registered Enterprises as Resident Enterprises in Accordance With the De Facto Standards of Organizational Management, or Circular 82, which provides certain specific criteria for determining whether the “de facto management body” of a PRC-controlled enterprise that is incorporated offshore is located in China. Although this Circular only applies to offshore enterprises controlled by PRC enterprises or PRC enterprise groups, not those controlled by PRC individuals or foreigners, the criteria set forth in the circular may reflect the SAT’s general position on how the “de facto management body” text should be applied in determining the tax resident status of all offshore enterprises. According to Circular 82, an offshore incorporated enterprise controlled by a PRC enterprise or a PRC enterprise group will be regarded as a PRC tax resident by virtue of having its “de facto management body” in China and will be subject to PRC enterprise income tax on its global income if all of the following conditions are met: (i) the primary location of the day-to-day operational management is in China; (ii) decisions relating to the enterprise’s financial and human resource matters are made or are subject to approval

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by organizations or personnel in China; (iii) the enterprise’s primary assets, accounting books and records, company seals, and board and shareholder resolutions, are located or maintained in China; and (iv) at least 50% of voting board members or senior executives habitually reside in China.

Our PRC counsel, JunHe LLP, has advised us that, based on its understanding of the current PRC Laws and Regulations, I-Mab should not be considered as a PRC resident enterprise for PRC tax income purposes. However, the tax resident status of an enterprise is subject to determination by the PRC tax authorities and uncertainties remain with respect to the interpretation of the term “de facto management body.” If the PRC tax authorities determine that we are a PRC resident enterprise for enterprise income tax purposes, we could be subject to PRC tax at a rate of 25% on our worldwide income, which could materially reduce our net income, and we may be required to withhold a 10% withholding tax from dividends we pay to our shareholders that are non-resident enterprises (including the holders of our ADSs). In addition, non-resident enterprise shareholders (including our ADS holders) may be subject to PRC tax at a rate of 10% on gains realized on the sale or other disposition of ADSs or ordinary shares, if such income is treated as sourced from within China. Furthermore, if we are deemed a PRC resident enterprise, dividends payable to our non-PRC individual shareholders (including our ADS holders) and any gain realized on the transfer of ADSs or ordinary shares by such shareholders may be subject to PRC tax at a rate of 20% in the case of non-PRC individuals (which in the case of dividends may be withheld at source) unless a reduced rate is available under an applicable tax treaty. It is unclear whether non-PRC shareholders of our company would be able to claim the benefits of any tax treaties between their country of tax residence and the PRC in the event that we are treated as a PRC resident enterprise. Any such tax may reduce the returns on your investment in the ADSs or ordinary shares.

Failure to renew our current leases or locate desirable alternatives for our leased properties could materially and adversely affect our business.

We lease properties for our offices and laboratories. We may not be able to successfully extend or renew such leases upon expiration of the current term on commercially reasonable terms or at all, and may therefore be forced to relocate our affected operations. This could disrupt our operations and result in significant relocation expenses, which could adversely affect our business, financial condition and results of operations. In addition, we compete with other businesses for premises at certain locations or of desirable sizes. As a result, even though we could extend or renew our leases, rental payments may significantly increase as a result of the high demand for the leased properties. In addition, we may not be able to locate desirable alternative sites for our current leased properties as our business continues to grow and failure in relocating our affected operations could adversely affect our business and operations.

Certain of our leasehold interests in leased properties have not been registered with the relevant PRC governmental authorities as required by relevant PRC laws. The failure to register leasehold interests may expose us to potential fines.

We have not registered certain of our lease agreements with the relevant government authorities. Under the relevant PRC laws and regulations, we may be required to register and file with the relevant government authority executed leases. The failure to register the lease agreements for our leased properties will not affect the validity of these lease agreements, but the competent housing authorities may order us to register the lease agreements in a prescribed period of time and impose a fine ranging from RMB1,000 to RMB10,000 for each non-registered lease if we fail to complete the registration within the prescribed timeframe.

We have granted, and may continue to grant, options and other types of awards under our share incentive plans, which may result in increased share-based compensation expenses.

We have adopted the Second Amended and Restated 2017 Employee Stock Option Plan (the “2017 Plan”), the Second Amended and Restated 2018 Employee Stock Option Plan (the “2018 Plan”), the 2019 Share Incentive Plan (the “2019 Plan”) and the 2020 Share Incentive Plan (the “2020 Plan”), for the purpose of granting

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share-based compensation awards to employees, directors and consultants to incentivize their performance and align their interests with ours. We recognize expenses in our consolidated financial statements in accordance with U.S. GAAP. As of the date of this prospectus supplement, the awards that had been granted to our directors, officers, employees and consultants and remained outstanding included (i) options to purchase an aggregate of 7,139,583 ordinary shares, 9,948,512 ordinary shares, 72,000 ordinary shares and 1,052,367 ordinary shares under the 2017 Plan, the 2018 Plan, the 2019 Plan and the 2020 Plan, respectively, excluding options that were forfeited, cancelled, or exercised after the relevant grant date; and (ii) restricted share units to receive an aggregate of 5,106,138 ordinary shares under the 2020 Plan, excluding restricted share units that were forfeited, cancelled, or vested after the relevant grant date.

We believe the granting of share-based compensation is of significant importance to our ability to attract and retain key personnel and employees, and we will continue to grant share-based compensation to employees in the future. As a result, our expenses associated with share-based compensation may increase, which may have an adverse effect on our results of operations. We may re-evaluate the vesting schedules, lock-up period, exercise price or other key terms applicable to the grants under our currently effective share incentive plans from time to time. If we choose to do so, we may experience substantial change in our share-based compensation charges.

Fluctuations in exchange rates could have a material and adverse effect on our results of operations and the value of your investment.

The conversion of RMB into foreign currencies, including U.S. dollars, is based on rates set by the People’s Bank of China. The RMB has fluctuated against the U.S. dollar, at times significantly and unpredictably. The value of RMB against the U.S. dollar and other currencies is affected by changes in China’s political and economic conditions and by China’s foreign exchange policies, among other things. We cannot assure you that RMB will not appreciate or depreciate significantly in value against the U.S. dollar in the future. It is difficult to predict how market forces or PRC or U.S. government policy may impact the exchange rate between RMB and the U.S. dollar in the future.

Any significant appreciation or depreciation of RMB may materially and adversely affect our revenues, earnings and financial position, and the value of, and any dividends payable on, our ADSs in U.S. dollars. For example, to the extent that we need to convert U.S. dollars we receive into RMB to pay our operating expenses, appreciation of RMB against the U.S. dollar would have an adverse effect on the RMB amount we would receive from the conversion. Conversely, a significant depreciation of RMB against the U.S. dollar may significantly reduce the U.S. dollar equivalent of our earnings, which in turn could adversely affect the price of our ADSs.

Very limited hedging options are available in China to reduce our exposure to exchange rate fluctuations. To date, we have not entered into any hedging transactions in an effort to reduce our exposure to foreign currency exchange risk. While we may decide to enter into hedging transactions in the future, the availability and effectiveness of these hedges may be limited and we may not be able to adequately hedge our exposure or at all. In addition, our currency exchange losses may be magnified by PRC exchange control regulations that restrict our ability to convert RMB into foreign currency. As a result, fluctuations in exchange rates may have a material adverse effect on your investment.

Certain PRC regulations may make it more difficult for us to pursue growth through acquisitions.

The Regulations on Mergers and Acquisitions of Domestic Enterprises by Foreign Investors, or the M&A Rules, adopted by six PRC regulatory agencies in 2006 and amended in 2009, established additional procedures and requirements that could make merger and acquisition activities by foreign investors more time-consuming and complex. Such regulation requires, among other things, that the Ministry of Commerce, or MOFCOM, be notified in advance of any change of control transaction in which a foreign investor acquires control of a PRC domestic enterprise and involves any of the following circumstances: (i) any important industry is concerned; (ii) such transaction involves factors that impact or may impact national economic security; or (iii) such

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transaction will lead to a change in control of a domestic enterprise which holds a famous trademark or PRC time-honored brand. We do not expect that this offering will trigger MOFCOM pre-notification under each of the above-mentioned circumstances or any review by other PRC government authorities, except as disclosed below in “—The approval of the CSRC may be required in connection with this offering, and, if required, we cannot predict whether we will be able to obtain such approval.” Moreover, the Anti-Monopoly Law promulgated by the Standing Committee of National People’s Congress which became effective in 2008 requires that transactions which are deemed concentrations and involve parties with specified turnover thresholds must be cleared by State Administration for Market Regulation (the “SAMR”), the successive authority of MOFCOM, before they can be completed.

We may rely on dividends and other distributions on equity paid by our PRC subsidiaries to fund any cash and financing requirements we may have, and any limitation on the ability of our PRC subsidiaries to make payments to us could have a material and adverse effect on our ability to conduct our business.

We are a Cayman Islands holding company and we may rely on dividends and other distributions on equity paid by our PRC subsidiaries for our cash and financing requirements, including the funds necessary to pay dividends and other cash distributions to our shareholders and service any debt we may incur. If any of our PRC subsidiaries incur debt on its own behalf in the future, the instruments governing the debt may restrict their ability to pay dividends or make other distributions to us. Under PRC laws and regulations, our PRC subsidiaries, each of which is a wholly foreign-owned enterprise may pay dividends only out of its respective accumulated profits as determined in accordance with PRC accounting standards and regulations. In addition, a wholly foreign-owned enterprise is required to set aside at least 10% of its after-tax profits each year, if any, to fund a certain statutory reserve fund, until the aggregate amount of such fund reaches 50% of its registered capital. At its discretion, a wholly foreign-owned enterprise may allocate a portion of its after-tax profits based on PRC accounting standards to a staff welfare and bonus fund. The reserve fund and staff welfare and bonus fund cannot be distributed to us as dividends.

Our PRC subsidiaries generate primarily all of their revenue in RMB, which is not freely convertible into other currencies. As result, any restriction on currency exchange may limit the ability of our PRC subsidiaries to use their RMB revenues to pay dividends to us.

The PRC government may continue to strengthen its capital controls, and more restrictions and a substantial vetting process may be put forward by SAFE for cross-border transactions falling under both the current account and the capital account. Any limitation on the ability of our PRC subsidiaries to pay dividends or make other kinds of payments to us could materially and adversely limit our ability to grow, make investments or acquisitions that could be beneficial to our business, pay dividends, or otherwise fund and conduct our business.

In addition, the PRC Enterprise Income Tax Law and its implementation rules provide that a withholding tax rate of up to 10% will be applicable to dividends payable by PRC companies to non-PRC-resident enterprises unless otherwise exempted or reduced according to treaties or arrangements between the PRC central government and governments of other countries or regions where the non-PRC-resident enterprises are incorporated.

PRC regulations relating to offshore investment activities by PRC residents may limit our PRC subsidiaries’ ability to change their registered capital or distribute profits to us or otherwise expose us or our PRC resident beneficial owners to liability and penalties under PRC laws.

In July 2014, SAFE promulgated the Circular on Relevant Issues Concerning Foreign Exchange Control on Domestic Residents’ Offshore Investment and Financing and Roundtrip Investment Through Special Purpose Vehicles, or SAFE Circular 37. SAFE Circular 37 requires PRC residents (including PRC individuals and PRC corporate entities as well as foreign individuals that are deemed as PRC residents for foreign exchange administration purpose) to register with SAFE or its local branches in connection with their direct or indirect

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offshore investment activities. SAFE Circular 37 further requires amendment to the SAFE registrations in the event of any changes with respect to the basic information of the offshore special purpose vehicle, such as changes of a PRC individual shareholder, name and operation term, or any significant changes with respect to the offshore special purpose vehicle, such as increase or decrease of capital contribution, share transfer or exchange, or mergers or divisions. SAFE Circular 37 is applicable to our shareholders who are PRC residents. If our shareholders who are PRC residents fail to make the required registration or to update the previously filed registration, our PRC subsidiaries may be prohibited from distributing their profits or the proceeds from any capital reduction, share transfer or liquidation to us, and we may also be prohibited from making additional capital contributions into our PRC subsidiaries.

In February 2015, SAFE promulgated a Notice on Further Simplifying and Improving Foreign Exchange Administration Policy on Direct Investment, or SAFE Notice 13, effective June 2015. Under SAFE Notice 13, applications for foreign exchange registration of inbound foreign direct investments and outbound overseas direct investments, including those required under SAFE Circular 37, will be filed with qualified banks instead of SAFE. The qualified banks will directly examine the applications and accept registrations under the supervision of SAFE.

All of our shareholders who we are aware of being subject to the SAFE regulations have completed the initial registrations with the local SAFE branch or qualified banks as required by SAFE Circular 37. However, we may not be informed of the identities of all the PRC residents holding direct or indirect interests in our company, and we cannot provide any assurance that these PRC residents will comply with our request to make or obtain any applicable registrations or continuously comply with all requirements under SAFE Circular 37 or other related rules. The failure or inability of the relevant shareholders to comply with the registration procedures set forth in these regulations may subject us to fines and legal sanctions, such as restrictions on our cross-border investment activities, on the ability of our wholly foreign-owned subsidiaries in China to distribute dividends and the proceeds from any reduction in capital, share transfer or liquidation to us. Moreover, failure to comply with the various foreign exchange registration requirements described above could result in liability under PRC law for circumventing applicable foreign exchange restrictions. As a result, our business operations and our ability to distribute profits could be materially and adversely affected.

Any failure to comply with PRC regulations regarding our employee equity incentive plans may subject the PRC plan participants or us to fines and other legal or administrative sanctions.

We and our directors, executive officers and other employees who are PRC citizens or who have resided in China for a continuous period of not less than one year and who will be granted restricted shares or options are subject to the Notice on Issues Concerning the Foreign Exchange Administration for Domestic Individuals Participating in Stock Incentive Plan of Overseas Publicly Listed Company, issued by SAFE in February 2012, according to which, employees, directors, supervisors and other management members participating in any share incentive plan of an overseas publicly listed company who are PRC citizens or who are non-PRC citizens residing in China for a continuous period of not less than one year, subject to limited exceptions, are required to register with SAFE through a domestic qualified agent, which could be a PRC subsidiary of such overseas listed company, and complete certain other procedures. In addition, an overseas entrusted institution must be retained to handle matters in connection with the exercise or sale of stock options and the purchase or sale of shares and interests. Failure to complete the SAFE registrations may subject them to fines and legal sanctions and may also limit our ability to make payments under our equity incentive plans or receive dividends or sales proceeds related thereto, or our ability to contribute additional capital into our wholly foreign-owned enterprises in China and limit our wholly foreign-owned enterprises’ ability to distribute dividends to us. We also face regulatory uncertainties that could restrict our ability to adopt additional equity incentive plans for our directors and employees under PRC law.

In addition, the SAT has issued circulars concerning employee share options or restricted shares. Under these circulars, employees working in China who exercise share options, or whose restricted shares vest, will be

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subject to PRC individual income tax. The PRC subsidiaries of an overseas listed company have obligations to file documents related to employee share options or restricted shares with relevant tax authorities and to withhold individual income taxes of those employees related to their share options or restricted shares. If the employees fail to pay, or the PRC subsidiaries fail to withhold applicable income taxes, the PRC subsidiaries may face sanctions imposed by the tax authorities or other PRC government authorities.

PRC regulation of loans to and direct investment in PRC entities by offshore holding companies and governmental control of currency conversion may delay or prevent us from making loans to our PRC subsidiaries or making additional capital contributions to our wholly foreign-owned subsidiaries in China, which could materially and adversely affect our liquidity and our ability to fund and expand our business.

We are an offshore holding company conducting our operations in China through our PRC subsidiaries. We may make loans to our PRC subsidiaries subject to the approval from governmental authorities and limitation on the available loan amount, or we may make additional capital contributions to our wholly foreign-owned subsidiaries in China.

Any loans to our wholly foreign-owned subsidiaries in China, which are treated as foreign-invested enterprises under PRC law, are subject to PRC regulations and foreign exchange loan registrations. For example, loans by us to our wholly foreign-owned subsidiaries in China to finance their activities cannot exceed statutory limits and must be registered with the local counterpart of SAFE. In addition, a foreign-invested enterprise shall use its capital pursuant to the principle of authenticity and self-use within its business scope. The capital of a foreign-invested enterprise shall not be used for the following purposes: (i) directly or indirectly used for payment beyond the business scope of the enterprises or the payment prohibited by relevant laws and regulations; (ii) directly or indirectly used for investment in securities or investments other than banks’ principal-secured products unless otherwise provided by relevant laws and regulations; (iii) the granting of loans to non-affiliated enterprises, except where it is expressly permitted in the business license; and (iv) paying the expenses related to the purchase of real estate that is not for self-use (except for the foreign-invested real estate enterprises).

SAFE promulgated the Notice of the State Administration of Foreign Exchange on Reforming the Administration of Foreign Exchange Settlement of Capital of Foreign-invested Enterprises, or SAFE Circular 19, effective June 2015, in replacement of the Circular on the Relevant Operating Issues Concerning the Improvement of the Administration of the Payment and Settlement of Foreign Currency Capital of Foreign-Invested Enterprises, the Notice from the State Administration of Foreign Exchange on Relevant Issues Concerning Strengthening the Administration of Foreign Exchange Businesses, and the Circular on Further Clarification and Regulation of the Issues Concerning the Administration of Certain Capital Account Foreign Exchange Businesses. According to SAFE Circular 19, the flow and use of RMB capital converted from foreign currency-denominated registered capital of a foreign-invested company is regulated such that RMB capital may not be used for the issuance of RMB entrusted loans, the repayment of inter-enterprise loans or the repayment of banks loans that have been transferred to a third party. Although SAFE Circular 19 allows RMB capital converted from foreign currency-denominated registered capital of a foreign-invested enterprise to be used for equity investments within China, it also reiterates the principle that RMB converted from the foreign currency-denominated capital of a foreign-invested company may not be directly or indirectly used for purposes beyond its business scope. Thus, it is unclear whether SAFE will permit such capital to be used for equity investments in China in actual practice. SAFE promulgated the Notice of the State Administration of Foreign Exchange on Reforming and Standardizing the Foreign Exchange Settlement Management Policy of Capital Account, or SAFE Circular 16, effective on June 9, 2016, which reiterates some of the rules set forth in SAFE Circular 19, but changes the prohibition against using RMB capital converted from foreign currency-denominated registered capital of a foreign-invested company to issue RMB entrusted loans to a prohibition against using such capital to issue loans to non-associated enterprises. Violations of SAFE Circular 19 and SAFE Circular 16 could result in administrative penalties. SAFE Circular 19 and SAFE Circular 16 may significantly limit our ability to transfer any foreign currency we hold, including the net proceeds from our initial public offering, to our PRC subsidiaries, which may adversely affect our liquidity and our ability to fund and expand our business in China.

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In light of the various requirements imposed by PRC regulations on loans to and direct investment in PRC entities by offshore holding companies, we cannot assure you that we will be able to complete the necessary government registrations or obtain the necessary government approvals on a timely basis, if at all, with respect to future loans to our PRC subsidiaries or future capital contributions by us to our wholly foreign-owned subsidiaries in China. As a result, uncertainties exist as to our ability to provide prompt financial support to our PRC subsidiaries when needed. If we fail to complete such registrations or obtain such approvals, our ability to use foreign currency, including the proceeds we received from our initial public offering, to capitalize or otherwise fund our PRC operations may be negatively affected, which could materially and adversely affect our liquidity and our ability to fund and expand our business.

We and our shareholders face uncertainties with respect to indirect transfers of equity interests in PRC resident enterprises or other assets attributable to a PRC establishment of a non-PRC company.

On February 3, 2015, the SAT issued the Bulletin on Issues of Enterprise Income Tax and Indirect Transfers of Assets by Non-PRC Resident Enterprises, or Bulletin 7. Pursuant to this Bulletin, an “indirect transfer” of “PRC taxable assets,” including equity interests in a PRC resident enterprise, by non-PRC resident enterprises may be recharacterized and treated as a direct transfer of PRC taxable assets, if such arrangement does not have a reasonable commercial purpose and was established for the purpose of avoiding payment of PRC enterprise income tax. As a result, gains derived from such indirect transfer may be subject to PRC enterprise income tax. When determining whether there is a “reasonable commercial purpose” of the transaction arrangement, factors to be taken into consideration include: whether the main value of the equity interest of the relevant offshore enterprise derives from PRC taxable assets; whether the assets of the relevant offshore enterprise mainly consist of direct or indirect investment in China or if its income mainly derives from China; whether the offshore enterprise and its subsidiaries directly or indirectly holding PRC taxable assets have real commercial nature which is evidenced by their actual function and risk exposure; the duration of existence of the business model and organizational structure; the replicability of the transaction by direct transfer of PRC taxable assets; and the tax situation of such indirect transfer and applicable tax treaties or similar arrangements. On October 17, 2017, the SAT issued the Announcement of the State Administration of Taxation on Issues Concerning the Withholding of Non-resident Enterprise Income Tax at Source, or Bulletin 37, which came into effect on December 1, 2017. Bulletin 37 further clarifies the practice and procedure of the withholding of non-resident enterprise income tax.

Late payment of applicable tax will subject the transferor to default interest. Gains derived from the sale of shares by investors are not subject to the PRC enterprise income tax pursuant to Bulletin 7 where such shares were acquired in a transaction through a public stock exchange. However, the sale of ADSs or ordinary shares by a non-PRC resident enterprise outside a public stock exchange may be subject to PRC enterprise income tax under Bulletin 7.

There are uncertainties as to the application of Bulletin 7. Bulletin 7 may be determined by the tax authorities to be applicable to the sale of the shares of our offshore subsidiaries or investments where PRC taxable assets are involved. The transferors and transferees may be subject to the tax filing and withholding or tax payment obligation, while our PRC subsidiaries may be requested to assist in the filing. Furthermore, we, our non-resident enterprises and PRC subsidiaries may be required to spend valuable resources to comply with Bulletin 7 or to establish that we and our non-resident enterprises should not be taxed under Bulletin 7, for our previous and future restructuring or disposal of shares of our offshore subsidiaries, which may have a material adverse effect on our financial condition and results of operations.

The PRC tax authorities have the discretion under Bulletin 7 to make adjustments to the taxable capital gains based on the difference between the fair value of the taxable assets transferred and the cost of investment. If the PRC tax authorities make adjustments to the taxable income of the transactions under Bulletin 7 / Bulletin 37, our income tax costs associated with such potential acquisitions or disposals will increase, which may have an adverse effect on our financial condition and results of operations.

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The approval of the CSRC may be required in connection with this offering, and, if required, we cannot predict whether we will be able to obtain such approval.

The M&A Rules require overseas special purpose vehicles that are controlled by PRC companies or individuals and formed for the purpose of seeking a public listing on an overseas stock exchange through acquisitions of PRC domestic companies using shares of such special purpose vehicles or held by its shareholders as consideration to obtain the approval of the CSRC, prior to the listing and trading of such special purpose vehicle’s securities on an overseas stock exchange. However, the application of the M&A Rules remains unclear. If CSRC approval is required, it is uncertain whether it would be possible for us to obtain the approval, and any failure to obtain or delay in obtaining CSRC approval for this offering would subject us to sanctions imposed by the CSRC and other PRC regulatory agencies.

Our PRC counsel has advised us based on their understanding of the current PRC laws, rules and regulations that the CSRC’s approval may not be required for the listing and trading of our ADSs on the Nasdaq Stock Market in the context of this offering, given that: (i) the CSRC currently has not issued any definitive rule or interpretation concerning whether offerings like ours in this prospectus supplement are subject to this regulation, (ii) I-Mab Tianjin was not acquired by a connected merger or by acquisition of equity interest or assets of a PRC domestic company owned by PRC companies or individuals as defined under the M&A Rules, (iii) I-Mab Shanghai and I-Mab Hangzhou were incorporated as wholly foreign-owned enterprises by means of direct investment, and (iv) our other three PRC subsidiaries, including Tasgen (Chengdu) Bio-Tech Co., Ltd. (“Tasgen Chengdu”), Shanghai Tianyunjian Bio-Tech Co., Ltd. (“Shanghai Tianyunjian”) and Sanjing (Beijing) Biotechnology Co., Ltd. (“Sanjing Beijing”), belong to the reinvestment enterprises of foreign investment enterprises.

However, our PRC counsel has further advised us that there remain some uncertainties as to how the M&A Rules will be interpreted or implemented in the context of an overseas offering and its opinions summarized above are subject to any new laws, rules and regulations or detailed implementations and interpretations in any form relating to the M&A Rules. We cannot assure you that relevant PRC government agencies, including the CSRC, would reach the same conclusion as our PRC counsel. If it is determined that CSRC approval is required for this offering, we may face sanctions by the CSRC or other PRC regulatory agencies for failure to seek CSRC approval for this offering. These sanctions may include fines and penalties on our operations in China, limitations on our operating privileges in China, restrictions on or prohibition of the payments or remittance of dividends by our subsidiaries in China, or other actions that could have a material and adverse effect on our business, financial condition, results of operations, reputation and prospects, as well as the trading price of our ADSs. The CSRC or other PRC regulatory agencies may also take actions requiring us, or making it advisable for us, to halt this offering before the settlement and delivery of the ADSs in this offering. Consequently, if you engage in market trading or other activities in anticipation of and prior to the settlement and delivery of the ADSs in this offering, you would be doing so at the risk that the settlement and delivery may not occur. In addition, if the CSRC or other regulatory agencies later promulgate new rules or explanations requiring that we obtain their approvals for this offering, we may be unable to obtain a waiver of such approval requirements, if and when procedures are established to obtain such a waiver.

Recent litigation and negative publicity surrounding China-based companies listed in the U.S. may result in increased regulatory scrutiny of us and negatively impact the trading price of the ADSs and could have a material adverse effect upon our business, including our results of operations, financial condition, cash flows and prospects.

We believe that litigation and negative publicity surrounding companies with operations in China that are listed in the U.S. have negatively impacted stock prices for such companies. Various equity-based research organizations have published reports on China-based companies after examining, among other things, their corporate governance practices, related party transactions, sales practices and financial statements that have led to special investigations and stock suspensions on national exchanges. Any similar scrutiny of us, regardless of

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its lack of merit, could result in a diversion of management resources and energy, potential costs to defend ourselves against rumors, decreases and volatility in the ADS trading price, and increased directors and officers insurance premiums and could have a material adverse effect upon our business, including our results of operations, financial condition, cash flows and prospects.

General Risks Related to Our ADSs and this Offering

The trading price of our ADSs may be volatile, which could result in substantial losses to you.

The trading price of our ADSs ranged from US$9.30 to US$47.46 per ADS since the listing of ADSs on Nasdaq. The trading price of our ADSs can be volatile and fluctuate widely in response to a variety of factors, many of which are beyond our control. In addition, the performance and fluctuation of the market prices of other companies with business operations located mainly in the PRC that have listed their securities in the United States may affect the volatility in the price of and trading volumes for our ADSs. Some of these companies have experienced significant volatility. The trading performances of these PRC companies’ securities may affect the overall investor sentiment towards other PRC companies listed in the United States and consequently may impact the trading performance of our ADSs.

In addition to market and industry factors, the price and trading volume for our ADSs may be highly volatile for specific business reasons, including:

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In addition, the stock market, in general, and pharmaceutical and biotechnology companies have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. Broad market and industry factors may negatively affect the market price of our ADSs, regardless of our actual operating performance. Further, the current volatility in the financial markets and related factors beyond our control may cause the market price of our ADSs to decline rapidly and unexpectedly.

We may face an increased risk of securities class action litigation.

Historically, securities class action litigation has often been brought against a company following a significant decline in the market price of its securities. This risk is especially relevant for us because biotechnology and biopharmaceutical companies have experienced significant share price volatilities in recent years. If we were to face lawsuits, it could lead to substantial costs and a distraction of management’s attention and resources, which could harm our business.

We cannot guarantee that any share repurchase program will be fully consummated or that any share repurchase program will enhance long-term shareholder value, and share repurchases could increase the volatility of the price of our ADSs and could diminish our cash reserves.

On July 15, 2020, we announced that our board of directors has authorized a share repurchase program, pursuant to which we were authorized to repurchase our own ordinary shares, in the form of ADSs, with an aggregate value of up to US$20.0 million during a twelve-month period effective upon and from the date on which a formal stock repurchase plan engagement agreement is signed with a qualified broker-dealer(s). From July 15, 2020 to the date of this prospectus supplement, we didn’t repurchase any ADSs. Our share repurchase program could affect the price of our ADSs and increase volatility and may be suspended or terminated at any time.

If securities or industry analysts do not publish research or publish inaccurate or unfavorable research about our business, or if they adversely change their recommendations regarding our ADSs, the market price for our ADSs and trading volume could decline.

The trading market for our ADSs will depend in part on the research and reports that securities or industry analysts publish about us or our business. If research analysts do not establish and maintain adequate research

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coverage or if one or more of the analysts who covers us downgrades our ADSs or publishes inaccurate or unfavorable research about our business, the market price for our ADSs would likely decline. If one or more of these analysts cease coverage of our company or fail to publish reports on us regularly, we could lose visibility in the financial markets, which, in turn, could cause the market price or trading volume for our ADSs to decline.

Because we do not expect to pay dividends in the foreseeable future, you must rely on price appreciation of our ADSs for return on your investment.

We currently intend to retain most, if not all, of our available funds and any future earnings to fund the development and growth of our business. As a result, we do not expect to pay any cash dividends in the foreseeable future. Therefore, you should not rely on an investment in our ADSs as a source for any future dividend income.

Our board of directors has complete discretion as to whether to distribute dividends, subject to our memorandum and articles of association and certain requirements of Cayman Islands law. In addition, our shareholders may by ordinary resolution declare a dividend, but no dividend may exceed the amount recommended by our directors. Under Cayman Islands law, a Cayman Islands company may pay a dividend out of either profit or share premium account of the company, provided that in no circumstances may a dividend be paid out of share premium if this would result in the company being unable to pay its debts as they fall due in the ordinary course of business. Even if our board of directors decides to declare and pay dividends, the timing, amount and form of future dividends, if any, will depend on our future results of operations and cash flow, our capital requirements and surplus, the amount of distributions, if any, received by us from our subsidiaries, our financial condition, contractual restrictions and other factors deemed relevant by our board of directors. Accordingly, the return on your investment in our ADSs will likely depend entirely upon any future price appreciation of our ADSs. There is no guarantee that our ADSs will appreciate in value or even maintain the price at which you purchased the ADSs. You may not realize a return on your investment in our ADSs and you may even lose your entire investment in our ADSs.

Substantial future sales or perceived potential sales of our ADSs in the public market could cause the price of our ADSs to decline.

Sales of substantial amounts of our ADSs in the public market or the perception that these sales could occur, could adversely affect the market price of our ADSs and could materially impair our ability to raise capital through equity offerings in the future. The ADSs sold in our initial public offering and this offering will be freely tradable without restriction or further registration under the Securities Act. On December 14, 2020, the SEC declared effective a registration statement on Form F-1, under which the selling shareholders identified therein may offer, from time to time, up to 25,123,751 ordinary shares, including ordinary shares represented by ADSs of our company. Our remaining ordinary shares issued and outstanding will be available for sale in the public market subject to volume and other restrictions as applicable under Rules 144 and 701 under the Securities Act. In connection with this offering, we, certain directors and certain selling shareholders have agreed, except in this offering, not to sell any ordinary shares or ADSs for 90 days after the date of this prospectus supplement without the prior written consent of the underwriters, subject to certain exceptions. However, the underwriters may release these securities from these restrictions at any time, subject to applicable regulations of the Financial Industry Regulatory Authority, Inc. We cannot predict what effect, if any, market sales of securities held by our significant shareholders or any other shareholder or the availability of these securities for future sale will have on the market price of our ADSs. See “Underwriting” and “Shares Eligible for Future Sales” for a more detailed description of the restrictions on selling our securities after this offering.

The voting rights of holders of ADSs are limited by the terms of the deposit agreement, and you may not be able to exercise the same rights as our shareholders.

Holders of ADSs do not have the same rights as our shareholders. As a holder of our ADSs, you will not have any direct right to attend general meetings of our shareholders or to cast any votes at such meetings. As an

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ADS holder, you will only be able to exercise the voting rights carried by the underlying ordinary shares indirectly by giving voting instructions to the depositary in accordance with the provisions of the deposit agreement. Under the deposit agreement, you may vote only by giving voting instructions to the depositary. Upon receipt of your voting instructions, the depositary will try, as far as is practicable, to vote the ordinary shares underlying your ADSs in accordance with your instructions. If we ask for your instructions, then upon receipt of your voting instructions, the depositary will try to vote the underlying ordinary shares in accordance with these instructions. If we do not instruct the depositary to ask for your instructions, the depositary may still vote in accordance with instructions you give, but it is not required to do so. You will not be able to directly exercise your right to vote with respect to the underlying ordinary shares unless you withdraw the shares, and become the registered holder of such shares prior to the record date for the general meeting. When a general meeting is convened, you may not receive sufficient advance notice of the meeting to withdraw the shares underlying your ADSs and become the registered holder of such shares to allow you to attend the general meeting and to vote directly with respect to any specific matter or resolution to be considered and voted upon at the general meeting. In addition, under our memorandum and articles of association, for the purposes of determining those shareholders who are entitled to attend and vote at any general meeting, our directors may close our register of members and/or fix in advance a record date for such meeting, and such closure of our register of members or the setting of such a record date may prevent you from withdrawing the ordinary shares underlying your ADSs and becoming the registered holder of such shares prior to the record date, so that you would not be able to attend the general meeting or to vote directly. If we ask for your instructions, the depositary will notify you of the upcoming vote and will arrange to deliver our voting materials to you. We have agreed to give the depositary notice of shareholder meetings sufficiently in advance of such meetings. Nevertheless, we cannot assure you that you will receive the voting materials in time to ensure that you can instruct the depositary to vote the underlying ordinary shares represented by your ADSs. In addition, the depositary and its agents are not responsible for failing to carry out voting instructions or for their manner of carrying out your voting instructions. This means that you may not be able to exercise your right to direct how the shares underlying your ADSs are voted and you may have no legal remedy if the shares underlying your ADSs are not voted as you requested. In addition, in your capacity as an ADS holder, you will not be able to call a shareholders’ meeting. Except in limited circumstances, the depositary for our ADSs will give us a discretionary proxy to vote the ordinary shares underlying your ADSs if you do not vote at shareholders’ meetings, which could adversely affect your interests.

Under the deposit agreement for the ADSs, if you do not vote, the depositary will give us a discretionary proxy to vote the ordinary shares underlying your ADSs at shareholders’ meetings unless:

The effect of this discretionary proxy is that you cannot prevent our ordinary shares underlying your ADSs from being voted, except under the circumstances described above. This may make it more difficult for shareholders to influence the management of our company. Holders of our ordinary shares are not subject to this discretionary proxy.

Your right to participate in any future rights offerings may be limited, which may cause dilution to your holdings.

We may from time to time distribute rights to our shareholders, including rights to acquire our securities. However, we cannot make rights available to you in the United States unless we register both the rights and the

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securities to which the rights relate under the Securities Act or an exemption from the registration requirements is available. Under the deposit agreement, the depositary will not make rights available to you unless both the rights and the underlying securities to be distributed to ADS holders are either registered under the Securities Act or exempt from registration under the Securities Act. We are under no obligation to file a registration statement with respect to any such rights or securities or to endeavor to cause such a registration statement to be declared effective and we may not be able to establish a necessary exemption from registration under the Securities Act. Accordingly, you may be unable to participate in our rights offerings and may experience dilution in your holdings.

You may not receive cash dividends if the depositary decides it is impractical to make them available to you.

The depositary will pay cash dividends on the ADSs only to the extent that we decide to distribute dividends on our ordinary shares or other deposited securities, and we do not have any present plan to pay any cash dividends on our ordinary shares in the foreseeable future. To the extent that there is a distribution, the depositary of our ADSs has agreed to pay to you the cash dividends or other distributions it or the custodian receives on our ordinary shares or other deposited securities after deducting its fees and expenses pursuant to the deposit agreement. You will receive these distributions in proportion to the number of ordinary shares your ADSs represent. However, the depositary may, at its discretion, decide that it is inequitable or impractical to make a distribution available to any holders of ADSs. For example, the depositary may determine that it is not practicable to distribute certain property through the mail, or that the value of certain distributions may be less than the cost of mailing them. In these cases, the depositary may decide not to distribute such property to you.

You may be subject to limitations on transfer of your ADSs.

Your ADSs are transferable on the books of the depositary. However, the depositary may close its transfer books at any time or from time to time when it deems expedient in connection with the performance of its duties. The depositary may close its books from time to time for a number of reasons, including in connection with corporate events such as a rights offering, during which time the depositary needs to maintain an exact number of ADS holders on its books for a specified period. The depositary may also close its books in emergencies, and on weekends and public holidays. In addition, the depositary may refuse to deliver, transfer or register transfers of ADSs generally when our books or the books of the depositary are closed, or at any time if we or the depositary deems it advisable to do so because of any requirement of law or of any government or governmental body, or under any provision of the deposit agreement, or for any other reason.

Certain judgments obtained against us by our shareholders may not be enforceable.

We are an exempted company incorporated under the laws of the Cayman Islands. We conduct our operations in China and substantially all of our assets are located in China. In addition, our directors and executive officers, and some of the experts named in this prospectus supplement, reside within China, and most of the assets of these persons are located within China. As a result, it may be difficult or impossible for you to bring an action against us or against these individuals in the United States in the event that you believe that your rights have been infringed under the U.S. federal securities laws or otherwise. Even if you are successful in bringing an action of this kind, the laws of the Cayman Islands and of the PRC may render you unable to enforce a judgment against our assets or the assets of our directors and officers.

ADSs holders may not be entitled to a jury trial with respect to claims arising under the deposit agreement, which could result in less favorable outcomes to the plaintiff(s) in any such action.

The deposit agreement governing the ADSs representing our ordinary shares provides that, subject to the depositary’s right to require a claim to be submitted to the federal or state courts in the City of New York have jurisdiction to hear and determine claims arising under the deposit agreement and in that regard, to the fullest extent permitted by law, ADS holders waive the right to a jury trial of any claim they may have against us or the

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depositary arising out of or relating to our shares, the ADSs or the deposit agreement, including any claim under the U.S. federal securities laws. Also, we may amend or terminate the deposit agreement without your consent. If you continue to hold your ADSs after an amendment to the deposit agreement, you agree to be bound by the deposit agreement as amended.

If we or the depositary were to oppose a jury trial demand based on such waiver, the court would determine whether the waiver was enforceable in the facts and circumstances of that case in accordance with applicable state and federal law, including whether a party knowingly, intelligently and voluntarily waived the right to a jury trial. The waiver to right to a jury trial of the deposit agreement is not intended to be deemed a waiver by any holder or beneficial owner of ADSs of our or the depositary’s compliance with the U.S. federal securities laws and the rules and regulations promulgated thereunder.

If you or any other holders or beneficial owners of ADSs bring a claim against us or the depositary in connection with matters arising under the deposit agreement or the ADSs, including claims under U.S. federal securities laws, you or such other holder or beneficial owner may not be entitled to a jury trial with respect to such claims, which may have the effect of limiting and discouraging lawsuits against us and/or the depositary. If a lawsuit is brought against us and/or the depositary under the deposit agreement, it may be heard only by a judge or justice of the applicable trial court, in which the trial would be conducted according to different civil procedures and may result in different outcomes than a trial by jury would have had, including results that could be less favorable to the plaintiff(s) in any such action.

Nevertheless, if this jury trial waiver provision is not enforced, to the extent a court action proceeds, it would proceed under the terms of the deposit agreement with a jury trial. No condition, stipulation or provision of the deposit agreement or ADSs serves as a waiver by any holder or beneficial owner of ADSs or by us or the depositary of compliance with any substantive provision of the U.S. federal securities laws and the rules and regulations promulgated thereunder.

You may face difficulties in protecting your interests, and your ability to protect your rights through U.S. courts may be limited, because we are incorporated under Cayman Islands law.

We are an exempted company incorporated under the laws of the Cayman Islands with limited liability. Our corporate affairs are governed by our memorandum and articles of association, the Companies Act (2020 Revision) of the Cayman Islands, which we refer to as the Companies Act, and the common law of the Cayman Islands. The rights of shareholders to take action against our directors, actions by our minority shareholders and the fiduciary duties of our directors to us under Cayman Islands law are to a large extent governed by the common law of the Cayman Islands. The common law of the Cayman Islands is derived in part from comparatively limited judicial precedent in the Cayman Islands as well as from the common law of England, the decisions of whose courts are of persuasive authority, but are not binding, on a court in the Cayman Islands. The rights of our shareholders and the fiduciary duties of our directors under Cayman Islands law are not as clearly established as they would be under statutes or judicial precedent in some jurisdictions in the United States. In particular, the Cayman Islands has a less developed body of securities laws than the United States. Some U.S. states, such as Delaware, have more fully developed and judicially interpreted bodies of corporate law than the Cayman Islands. In addition, Cayman Islands companies may not have standing to initiate a shareholder derivative action in a federal court of the United States.

Shareholders of Cayman Islands exempted companies like us have no general rights under Cayman Islands law to inspect corporate records or to obtain copies of lists of shareholders of these companies. Our directors have discretion under our articles of association to determine whether or not, and under what conditions, our corporate records may be inspected by our shareholders, but are not obliged to make them available to our shareholders. This may make it more difficult for you to obtain the information needed to establish any facts necessary for a shareholder motion or to solicit proxies from other shareholders in connection with a proxy contest.

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As a result of all of the above, our public shareholders may have more difficulty in protecting their interests in the face of actions taken by management, members of the board of directors or controlling shareholders than they would as public shareholders of a company incorporated in the United States.

We will not receive any proceeds from this offering. However, we continue to retain broad discretion in the use of the net proceeds from our initial public offering.

We will not receive any proceeds from this offering; however, we will continue to retain broad discretion in the application of the net proceeds from our initial public offering and could spend the proceeds in ways that do not produce income or increase our ADS price. We have not determined a specific use for a portion of the net proceeds of our initial public offering, and our management will have considerable discretion in deciding how to apply these proceeds. You will not have the opportunity to assess whether the net proceeds from our initial public offering are being used appropriately before you make your investment decision. You must rely on the judgment of our management regarding the application of the net proceeds of our initial public offering. We cannot assure you that the net proceeds from our initial public offering will be used in a manner that would improve our results of operations or increase our ADS price, nor that these net proceeds will be placed only in investments that generate income or appreciate in value.

Our memorandum and articles of association contains anti-takeover provisions that could discourage a third party from acquiring us and adversely affect the rights of holders of our ordinary shares and the ADSs.

Our memorandum and articles of association contains provisions to limit the ability of others to acquire control of our company or cause us to engage in change of control transactions. These provisions could have the effect of depriving our shareholders of an opportunity to sell their shares at a premium over prevailing market prices by discouraging third parties from seeking to obtain control of our company in a tender offer or similar transaction. Our board of directors has the authority to issue preferred shares in one or more series and to fix their designations, powers, preferences, privileges, and relative participating, optional or special rights and the qualifications, limitations or restrictions, including dividend rights, conversion rights, voting rights, terms of redemption and liquidation preferences, any or all of which may be greater than the rights associated with our ordinary shares, in the form of ADS or otherwise. Preferred shares could be issued with terms calculated to delay or prevent a change in control of our company or make removal of management more difficult. If our board of directors decides to issue preferred shares, the price of our ADSs may fall and the voting and other rights of the holders of our ordinary shares and ADSs may be materially and adversely affected.

We are an emerging growth company within the meaning of the Securities Act and may take advantage of certain reduced reporting requirements.

We are an “emerging growth company,” as defined in the U.S. Jumpstart Our Business Startups Act of 2012, or the JOBS Act, and we may take advantage of certain exemptions from various requirements applicable to other public companies that are not emerging growth companies including, most significantly, not being required to comply with the auditor attestation requirements of Section 404 of Sarbanes-Oxley Act of 2002 for so long as we are an emerging growth company. As a result, if we elect not to comply with such auditor attestation requirements, our investors may not have access to certain information they may deem important.

The JOBS Act also provides that an emerging growth company does not need to comply with any new or revised financial accounting standards until such date that a private company is otherwise required to comply with such new or revised accounting standards. However, we have elected to “opt out” of this provision and, as a result, we will comply with new or revised accounting standards as required when they are adopted for public companies. This decision to opt out of the extended transition period under the JOBS Act is irrevocable.

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We are a foreign private issuer within the meaning of the rules under the Exchange Act, and as such we are exempt from certain provisions applicable to U.S. domestic public companies.

Because we qualify as a foreign private issuer under the Exchange Act, we are exempt from certain provisions of the securities rules and regulations in the United States that are applicable to U.S. domestic issuers, including:

We are required to file an annual report on Form 20-F within four months of the end of each fiscal year. In addition, we intend to publish our results on a quarterly basis as press releases, distributed pursuant to the rules and regulations of the Nasdaq Stock Market. Press releases relating to financial results and material events will also be furnished to the SEC on Form 6-K. However, the information we are required to file with or furnish to the SEC will be less extensive and less timely compared to that required to be filed with the SEC by U.S. domestic issuers. As a result, you may not be afforded the same protections or information that would be made available to you were you investing in a U.S. domestic issuer.

As an exempted company incorporated in the Cayman Islands, we are permitted to adopt certain home country practices in relation to corporate governance matters that differ significantly from the Nasdaq Stock Market’s corporate governance requirements; these practices may afford less protection to shareholders than they would enjoy if we complied fully with the Nasdaq Stock Market’s corporate governance requirements.

As a Cayman Islands company listed on the Nasdaq Stock Market, we are subject to the Nasdaq Stock Market’s corporate governance requirements. However, the Nasdaq Stock Market rules permit a foreign private issuer like us to follow the corporate governance practices of its home country. Certain corporate governance practices in the Cayman Islands, which is our home country, may differ significantly from the Nasdaq Stock Market’s corporate governance requirements. For example, neither the Companies Act nor our memorandum and articles of association requires a majority of our directors to be independent and we could include non-independent directors as members of our compensation committee and nominating committee, and our independent directors would not necessarily hold regularly scheduled meetings at which only independent directors are present. We follow home country practice with respect to adoption of the 2020 Plan. However, if we choose to follow home country practice in the future, our shareholders may be afforded less protection than they otherwise would under the Nasdaq Stock Market’s corporate governance requirements applicable to U.S. domestic issuers.

There can be no assurance that we will not be classified as a passive foreign investment company, or PFIC, for U.S. federal income tax purposes for any taxable year, which could subject U.S. investors in our ADSs or ordinary shares to significant adverse U.S. income tax consequences.

We will be a passive foreign investment company, or PFIC, for any taxable year if either (i) 75% or more of our gross income for such year consists of certain types of “passive” income or (ii) 50% or more of the average quarterly value of our assets (generally determined on the basis of fair market value) during such year produce or are held for the production of passive income (the “asset test”). No assurance can be given with respect to our PFIC status for the current taxable year or any future taxable year. The determination of whether we are or will

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become a PFIC is uncertain because it is a fact-intensive inquiry made on an annual basis that will depend, in part, on the composition of our income and assets. Fluctuations in the market price of our ADSs may cause us to be a PFIC for the current or subsequent taxable years because the value of our assets for purposes of the asset test may be determined by reference to the market price of our ADSs from time to time (which may be volatile for biopharmaceutical companies, such as ours, that have not yet achieved commercialization with respect to any of their products). The composition of our income and assets may also be affected by how, and how quickly, we use our liquid assets. Under circumstances where our revenue from activities that produce passive income increases relative to our revenue from activities that produce non-passive income, or where we determine not to deploy cash for active purposes, our risk of being a PFIC will substantially increase. Furthermore, prior to the commercialization of any of our drug candidates, interest and other passive income could constitute more than 75% of gross income for any taxable year. Because there are uncertainties in the application of the relevant rules, it is possible that the IRS may challenge our classification or valuation of certain income and assets, each of which may result in our being or becoming a PFIC for the current or subsequent taxable years.

If we are a PFIC in any taxable year, a U.S. Holder (as defined in “Taxation—United States Federal Income Tax Considerations”) may incur significantly increased U.S. income tax on gain recognized on the sale or other disposition of the ADSs or ordinary shares and on the receipt of distributions on the ADSs or ordinary shares to the extent such gain or distribution is treated as an “excess distribution” under the U.S. federal income tax rules and such holder may be subject to burdensome reporting requirements. Further, if we are a PFIC for any year during which a U.S. Holder holds our ADSs or ordinary shares, we generally will continue to be treated as a PFIC for all succeeding years during which such U.S. Holder holds our ADSs or ordinary shares. For more information see “Taxation—United States Federal Income Tax Considerations—Passive Foreign Investment Company Considerations.”

We expect to incur increased costs and become subject to additional rules and regulations as a result of being a public company.

As a public company, we expect to incur significant legal, accounting and other expenses that we did not incur as a private company. The Sarbanes-Oxley Act of 2002, as well as rules subsequently implemented by the SEC and the Nasdaq Global Market, impose various requirements on the corporate governance practices of public companies. As a company with less than US$1.07 billion in net revenues for our last fiscal year, we qualify as an “emerging growth company” pursuant to the JOBS Act. An emerging growth company may take advantage of specified reduced reporting and other requirements that are otherwise applicable generally to public companies. These provisions include exemption from the auditor attestation requirement under Section 404 of the Sarbanes-Oxley Act of 2002 in the assessment of the emerging growth company’s internal control over financial reporting and permission to delay adopting new or revised accounting standards until such time as those standards apply to private companies. However, we have elected to “opt out” of the provision that allows us to delay adopting new or revised accounting standards and, as a result, we will comply with new or revised accounting standards as required when they are adopted for public companies. This decision to opt out of the extended transition period under the JOBS Act is irrevocable.

We expect these rules and regulations to increase our legal and financial compliance costs and to make some corporate activities more time-consuming and costly. After we are no longer an “emerging growth company,” we expect to incur significant expenses and devote substantial management effort toward ensuring compliance with the requirements of Section 404 of the Sarbanes-Oxley Act of 2002 and the other rules and regulations of the SEC. We also expect that operating as a public company will make it more difficult and more expensive for us to obtain director and officer liability insurance, and we may be required to accept reduced policy limits and coverage or incur substantially higher costs to obtain the same or similar coverage. In addition, we will incur additional costs associated with our public company reporting requirements. It may also be more difficult for us to find qualified persons to serve on our board of directors or as executive officers. We are currently evaluating and monitoring developments with respect to these rules and regulations, and we cannot predict or estimate with any degree of certainty the amount of additional costs we may incur or the timing of such costs.

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In the past, shareholders of a public company often brought securities class action suits against the company following periods of instability in the market price of that company’s securities. If we were involved in a class action suit, it could divert a significant amount of our management’s attention and other resources from our business and operations, which could harm our results of operations and require us to incur significant expenses to defend the suit. Any such class action suit, whether or not successful, could harm our reputation and restrict our ability to raise capital in the future. In addition, if a claim is successfully made against us, we may be required to pay significant damages, which could have a material adverse effect on our financial condition and results of operations.

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BUSINESS

Overview

We are a clinical stage biopharmaceutical company committed to the discovery, development and commercialization of novel or highly differentiated biologics to treat diseases with significant unmet medical needs, particularly cancers and autoimmune disorders.

We were founded to capture the opportunities presented by the confluence of two major developments—the emergence of an attractive and growing biologics market in China, and the revolutionary scientific breakthroughs in cancer and autoimmune disease medicines. We believe we are well-positioned to become a biotech leader in China because of our innovative discovery expertise, fit-for-purpose technology platforms, biomarker-enabled translational medicine capabilities, and clinical development capabilities. These integrated capabilities are further enhanced by our deep understanding of China’s biologics regulatory framework and our direct access to extensive pre-clinical and clinical trial resources in China. To date, we have developed an innovative pipeline of more than 10 clinical and pre-clinical stage assets through our internal research and development efforts and in-licensing arrangements with global pharmaceutical and biotech companies.

Commercial Opportunities in China and Our Unique Position

We are fully aware of the competitive and regulatory challenges we face as an innovative clinical stage biotech company based in China, including need to raise significant capital, significant competition from global and other China-based biopharmaceutical companies, less streamlined regulatory pathway compared to countries with long-established regulatory systems, and potential implementation challenges and uncertainties of the recent government reform of the drug approval system. However, with these challenges in mind, we have been mitigating the risks through our internal R&D system that integrates multi-functional aspects of our drug development process to proactively deal with some of the regulatory challenges mentioned above. Furthermore, through our Beijing office which focuses on regulatory matters, we have established an effective communication channel with the regulatory agencies to discuss and resolve various regulatory issues promptly and effectively. We see vast opportunities for immuno-oncology and autoimmune biologics therapies in China. First, both the incidence and mortality of cancers in China have been increasing in recent years and are outpacing those in the United States and the rest of the world. Second, many innovative biologics approved to treat cancer and autoimmune diseases in the United States and Europe are not yet available in China. Third, the Chinese government has implemented new policies and regulations to simplify the review and approval cycle of clinical trials and new drug applications to encourage biologics innovation. Fourth, there has been a continuous and rapid increase in personal disposable income in China coupled with ongoing improvement in basic national health insurance coverage, making innovative biologics more accessible to more Chinese patients.

We believe we are uniquely positioned as a China-based global player to tap into these vast commercial opportunities. This is best demonstrated by our short journey in becoming one of the top clinical stage immunology companies in China. For example, in 2018 and 2019, we are the only China-based biotech company recognized by Genetic Engineering & Biotechnology News (GEN) as a top 10 immuno-oncology start-up in the world. To date, our research and development capabilities encompass discovery, translational medicine, biologics CMC development, pre-clinical development and clinical development with footprints in Shanghai, Beijing and the United States. We are now at a critical juncture to transition from a clinical stage biotech company into a fully integrated end-to-end global biopharmaceutical company in the next few years.

Our Unique Business Model

To achieve our mission and capitalize on these commercial opportunities, we have developed a business model built on two pillars: a fast-to-market China strategy and a fast-to-PoC (proof of concept) global strategy.

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Fast-to-Market China Strategy

Our fast-to-market China strategy focuses on seeking opportunities to in-license the development and commercialization rights of investigational drugs from global biopharmaceutical companies for Greater China. We only select investigational drugs that have the potential to become novel or highly differentiated medicines. Through our substantial in-house research and development efforts, we build additional data packages to meet the requirements of the National Medical Products Administration (the “NMPA”) to ensure programs are ready for late-stage or registrational clinical development. Our internal development capabilities combined with our deep insight into China’s regulatory framework and our clinical network enable us to efficiently navigate through the drug development process to registration. To date, we have built an innovative China Portfolio consisting of five investigational drugs with an aim for near-term product launch. All of these investigational drugs have met the related pre-set safety and preliminary efficacy endpoints in Phase 1 or Phase 2 clinical trials in Europe, the United States or elsewhere and are either in or ready for Phase 2 or Phase 3 clinical trials in China. Set forth below is a summary of the latest development status of the anchor assets in our China Portfolio:

As a result, the investigational drugs in our China Portfolio are positioned for a series of new drug applications (NDAs) in China with the submission of the first NDA expected in 2021.

Fast-to-PoC Global Strategy

Our fast-to-PoC global strategy focuses on advancing our own novel or differentiated biologics towards clinical validation in the United States. First, we seek PoC of these drug candidates in the United States by conducting early phase clinical trials with a set of safety and efficacy endpoints and leveraging the FDA’s streamlined regulatory system for innovative drug development, including a predictable timeline towards IND approval. Second, we will use the data generated to advance clinical development in China, which we believe confers several advantages, including access to China’s large patient pool, extensive clinical trial resources through collaborations with leading hospitals in China, and a regulatory pathway for fast-track approval of drugs supported by solid overseas clinical data. Building on this approach, we may out-license the global rights (excluding Greater China) of these investigational drugs following clinical validation in the United States, while

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retaining the Greater China rights for further development and commercialization. We believe this approach will allow Chinese patients to benefit from our most advanced treatments concurrently or soon after their market approvals elsewhere. To date, we have created a Global Portfolio that consists of two molecular classes—monoclonal antibodies and bi-specific antibodies, which are internally generated. They are highly innovative molecules compared to global competitor assets in the same or related classes of drug candidates. Set forth below is a summary of the latest development status of the anchor assets in our Global Portfolio:

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These two strategies and the resulting two portfolios complement each other. This enables us to achieve a balance among our ambition to develop novel or highly differentiated drugs, our goal to efficiently advance our pipeline assets towards commercialization and the inherent development risks. With this goal in mind, we are also aware that the intended novelty and key differentiation of our investigational drugs or drug candidates are subject to pivotal clinical validation and approval by the relevant regulatory authorities. There is no assurance that any such investigational drug or drug candidate will receive regulatory approval. See “Risk Factors” for a detailed description of the risks related to the development and commercialization of our drug candidates.

Our Capabilities

Our Innovative Discovery Expertise

Built by an elite group of seasoned immunologists with extensive academic research and drug development experience, our discovery engine has generated a panel of internally developed innovative drug molecules in a short span of five years. Among them, 12 innovative drug molecules have met our standard of novelty or high differentiation and have advanced toward further development. This achievement is a testament to our discovery team’s acumen and technical prowess in translating target biology into points of innovation or differentiation.

The discovery of lemzoparlimab showcases our innovative research capabilities. Not settling on performing routine or traditional antibody screening, we set a specific goal to identify and select a unique CD47 antibody that is free from binding to red blood cells (RBC) from all CD47 antibody leads. As a result, we selected by design, our proprietary CD47 antibody (TJC4) with a rare epitope that spares binding to RBCs as a differentiation point from other CD47 antibodies that typically cause inherent hematologic side effects. The topline results of the recently completed Phase 1a dose escalation monotherapy trial in the United States have demonstrated the differentiated profile of lemzoparlimab in drug safety and favorable pharmacokinetics in cancer patients. The key findings include: (i) lemzoparlimab was well tolerated up to 30 mg/kg on a weekly basis without priming dosing strategy, and no dose-limiting toxicity and no clinical or laboratory evidence of hemolytic anemia were observed throughout; (ii) lemzoparlimab PK appears to be linear at mid to high dose levels following a single dose with no significant “sink effect” and (iii) one confirmed Partial Response (PR) was observed in the 30 mg/kg cohort (N=3), and this patient had failed prior treatments with checkpoint inhibitors. Three patients achieved Stable Disease (SD). Therefore, we believe that lemzoparlimab, if approved, will be a potentially highly differentiated anti-tumor CD47 antibody with the advantage of minimizing hematologic side effects.

Another example of our R&D capability relates to our novel bi-specific antibody panel that represents a new wave of oncology drug candidates. We created novel biological properties of these bi-specific antibodies that are capable of enriching immune cells in tumors through dual targeting of PD-L1 and immune cells for a synergistic anti-tumor effect. These bi-specific drug candidates have been shown to exhibit unique properties that render tumors more responsive to treatment. Our discovery expertise, when combined with our “fit-for-purpose” antibody engineering technology platforms, becomes a powerful engine of innovation to create novel molecules.

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Our Fit-for-Purpose Technology Platforms

Our proprietary antibody engineering platforms enable us to accurately capture the biological properties of bi-specific antibodies and retain good manufacturability and druggability of the molecules. To date, we have eight novel pre-clinical stage bi-specific drug molecules. In addition to our own bi-specific antibody platform, we partnered with ABL Bio and WuXi Biologics to access their antibody engineering platforms in order to increase the probability of success, as different molecular configurations require different technologies. Furthermore, our proprietary antibody-cytokine technology has enabled another form of bi-specific antibodies such as TJ-L1I7 and TJ-C4GM that link a tumor-engaging antibody with an immune-modulatory cytokine. Superior to monoclonal antibodies or cytokines alone, this class of bi-specific antibodies has demonstrated unique properties of concentrating the drug molecules in tumors for a desired target effect with reduced systemic toxicity of cytokines or creating biologic synergy that can potentially translate into better treatment outcome.

Our Biomarker-Enabled Translational Medicine Capabilities

As we focus on developing innovative drug molecules, the ability to apply relevant biomarkers that link a drug response to treatment effects is critical for early-stage clinical trials of our investigational drugs. This translational medicine capability requires cross-functional knowledge and unique skills to link the target biology of an investigational drug to clinical responses. We have been developing tailor-made biomarkers for each of our investigational drugs, which are used to select potential responders, predict and measure target engagement, support dose determination and enable timely informed decisions on advancing our assets to the next phase of clinical development. For example, for the development of uliledlimab, we intend to use CD73 in tumor tissue in combination with other tumor biomarkers to stratify potential target patient populations in our clinical trial. To that end, we have developed assays to measure CD73 expression and activity in tumor tissues. Furthermore, we have developed specialized assays to measure uliledlimab drug concentrations in tumor tissues. By linking drug concentration with its activity in the same tumor location, these data help us determine appropriate dose selection for further clinical studies.

Our Clinical Development Capabilities

Our clinical development is led by a global team of clinical scientists, industry physicians and experts in portfolio management, quantitative science, clinical operations, drug safety and quality control. Our clinical team accounts for approximately 80% of our entire R&D organization’s headcount and 80% of our budget allocation. The skillset of our clinical development team is highlighted by a combination of extensive global pharma, local drug development and operation experiences with clinical networks in China and the United States. The team is driven by high ethical standards, with passion for improving the lives of patients.

Our team has the ability to integrate internal core development functions to conduct global and local clinical trials. We also effectively leverage external resources, including clinical contract research organizations, academic clinical centers and/or networks, and global pharmaceutical or biotech partnerships. Furthermore, we have established and implemented a robust internal clinical governance system and processes to safeguard patient safety and data integrity. Our current clinical development functions and teams are strategically based in Shanghai, Beijing, and the United States to cover Phase 1 through Phase 3 clinical trials in China and early-stage clinical trials in the United States.

Our clinical development capabilities are best demonstrated by the rapid implementation of 11 clinical trials, including one completed trial in the United States and ten on-going Phase 1/2 or registration trials in the United States and China in the past three years. To ensure regulatory approval and subsequent product launch as currently planned, we strive to reach the following critical clinical milestones by early 2021: 11 active clinical programs consisting of two Phase 3 or registrational trials in China, three Phase 2 trials and six Phase 1/2 trials in the United States and China.

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Our Global Strategic Collaborations

We have established an excellent track record of in-licensing and out-licensing deals with our global and regional partners. These in-licensing deals enable us to acquire multiple innovative clinical stage assets with favorable clinical data packages. We have quickly built our China Portfolio through in-licensing deals with global biotech partners, including MorphoSys, Genexine, MacroGenics and Ferring (as the sublicensee under our agreement with Ferring related to olamkicept). Over the past three years, we have established more than 10 global and regional partnerships with reputable pharma or biotech companies. Our partners selected us among many China-based companies with the belief that we are an ideal partner in China given our strength in science and drug development capability, our outstanding track record of execution demonstrated by rapidly progressing drug development programs in China and the United States, and our vision and network to tap into business opportunities and China’s growing pharmaceutical market. For example, MorphoSys, MacroGenics and Genexine all stated that we are an ideal or the best partner in China in their press releases or public announcements. The out-licensing deals enable us to streamline our pipeline, focus our resources on the most valuable assets in the most desirable territories and build strategic alliances with leading global biopharmaceutical companies. In addition, we seek co-development opportunities to share development costs, risks and territorial commercial rights with our partners. In the past several years, we have out-licensed four assets and initiated multiple co-development programs with partners such as ABL Bio, MSD, Roche and Junshi and WuXi Biologics. The revenue from out-licensing and co-development deals is expected to continue to grow as our pipeline progresses.

Global Strategic Partnership with AbbVie

In September 2020, we, through I-Mab Biopharma Co., Ltd. and I-Mab Biopharma US Limited, each a wholly-owned subsidiary of our company, entered into a broad global strategic collaboration with AbbVie Ireland Unlimited Company (“AbbVie”), a leading global, research-based biopharmaceutical company. Pursuant to this collaboration, we grant AbbVie a global license, excluding Mainland China, Hong Kong and Macau, to develop and commercialize lemzoparlimab. We retain all rights to develop and commercialize lemzoparlimab (as well as certain other compounds directed against CD47) in Mainland China, Hong Kong and Macau. AbbVie will conduct further global clinical trials (which we may elect to co-fund) to evaluate lemzoparlimab in multiple cancers. This deal also allows for potential collaboration on future CD47-related therapeutic agents, including CD47-based bispecific antibodies and combination therapies with lemzoparlimab and AbbVie’s venetoclax (Venclexta^®). Each party will have the opportunity, subject to rights of first negotiation to further licenses, to explore certain of each other’s related CD47-antibody programs in their respective territories. In addition, we and AbbVie will share manufacturing responsibilities, with AbbVie being the primary manufacturer for supply outside of Mainland China, Hong Kong and Macau and us being the primary manufacturer for supply in Mainland China, Hong Kong and Macau. We believe that this collaboration will accelerate the establishment of our commercial production operations in China.

Pursuant to this collaboration, AbbVie has paid us an upfront payment of US$180 million. Additionally, in connection with the recently released clinical data from the Phase 1 trial of lemzoparlimab in the United States, we expect to be paid a first milestone payment of US$20 million. We will also be eligible to receive up to US$1.74 billion in further success-based development, regulatory and sales milestone payments for lemzoparlimab, of which US$840 million are based on clinical development and regulatory approval milestones, with the remainder based on commercial milestones. Upon commercialization of lemzoparlimab, AbbVie will also pay tiered royalties from low double-digit percentages on global net sales outside of Mainland China, Hong Kong and Macau. In addition, AbbVie has a license and right of first negotiation to further develop and commercialize two additional lemzoparlimab-based bispecific antibodies discovered and currently being developed by us and we cannot commercialize products containing these two additional lemzoparlimab-based bispecific antibodies outside of Mainland China, Hong Kong and Macau even if AbbVie does not exercise its right of first negotiation or we are unable to come to financial terms on such products. The potential value of each such license is minimum US$500 million in upfront and milestone payments, for a combined total of no less than US$1 billion.

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This strategic collaboration with AbbVie reinforces our internal research and development capabilities and our leading position in immuno-oncology and enables us to realize the full potential of our innovation. By leveraging the combined development strength of our company and AbbVie, we aim to speed lemzoparlimab to market for patients in need around the world.

Our Drug Pipeline

The chart below summarizes the development status of our drug pipeline.

Notes:

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Highlights of Our Fast-to-Market China Portfolio

Our fast-to-market China strategy is demonstrated by our China Portfolio, which consists of novel or highly differentiated investigational drugs. Felzartamab, efineptakin, enoblituzumab and eftansomatropin are the four anchor assets in our China Portfolio. While we have been diligently pursuing our fast-to-market China strategy, we are aware that there is no assurance that we will always be successful in commercializing any of our product candidates in our China Portfolio in an accelerated manner. See “Risk Factors” for a detailed description of the risks related to the development and commercialization of our drug candidates.

Felzartamab is a differentiated CD38 antibody originally developed by MorphoSys that meets the pre-set clinical safety and preliminary efficacy endpoints from a clinical trial conducted in the European Union (EU). In-licensed from MorphoSys, felzartamab is being developed to address the current unmet needs and commercial opportunities in China for multiple myeloma and potentially autoimmune diseases, such as SLE. We own an exclusive license to develop felzartamab in Greater China. We believe felzartamab, if approved, is potentially highly differentiated compared with the currently marketed CD38 antibody. First, under a similar pre-medication condition with dexamethasone, anti-pyretics and anti-histamines, felzartamab has demonstrated a significantly shorter infusion time and lower infusion reaction rate. Second, unlike the currently marketed CD38 antibody, felzartamab does not down-regulate CD38 expression on the surface of bone marrow myeloma cells in vitro, maintaining sensitivity of myeloma cells to felzartamab for repeated treatments. We are conducting two parallel registrational trials with felzartamab as a third-line monotherapy and as a second line combination therapy with lenalidomide, both in patients with multiple myeloma in Greater China. The recruitment progress for these two trials remains on track. We aim to submit an NDA for felzartamab as a third-line monotherapy in 2021, followed by another NDA submission for felzartamab as a second-line combination therapy. Moreover, we believe felzartamab has great market potential in the treatment of pathogenic antibody-mediated autoimmune diseases, such as SLE, where there is a significant unmet need for more effective therapies. We submitted an IND application to the NMPA in October 2019 for a Phase 1b trial for felzartamab in SLE.

Efineptakin is the first long-acting recombinant human IL-7 known to boost cancer-fighting T lymphocytes by increasing their number and function and is being developed as a potential oncology investigational drug. The clinical safety and effect of efineptakin on T cells have been investigated in multiple previous and ongoing clinical trials in South Korea and the United States. Efineptakin is being positioned to address a huge unmet medical need in oncology. First, efineptakin can be an oncology-care agent to treat cancer treatment-related lymphopenia (low blood lymphocyte levels), a common condition that occurs in cancer patients who have received chemotherapy or radiation therapy, and there is no approved treatment for this condition. This condition causes further damage to patients’ already compromised immune system and weakens its ability to fight cancers. Second, efineptakin has been shown to synergize with a PD-1 antibody in a tumor animal model potentially through increased T lymphocyte activation and proliferation. In May 2020, we obtained regulatory clearance from the NMPA to initiate a phase 2 clinical trial with efineptakin in GBM patients with lymphopenia.

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We had the first patient in on December 31, 2020 and the first patient dosed on February 4, 2021. We are coordinating our study globally with Genexine, which is conducting a Phase 2 clinical trial in South Korea and parallel clinical trials in the United States towards clinical PoC.

Enoblituzumab is a humanized antibody directed at B7-H3, a member of the B7 family of T cell checkpoint regulators that is widely expressed across multiple tumor types and plays a key role in the regulation of immune response against cancers. Similar to other inhibitors of the B7 family such as PD-L1, targeting B7-H3 potentially provides a treatment option for a variety of cancers expressing B7-H3. Enoblituzumab was originally developed by MacroGenics, and we own the Greater China rights of this investigational drug. In multiple clinical trials conducted by MacroGenics, when combined with pembrolizumab in recurrent or metastatic squamous cell carcinoma of the head and neck (“SCCHN”) and non-small cell lung cancer (“NSCLC”), enoblituzumab has shown favorable clinical results that warrant further investigation. In the first quarter of 2021, MacroGenics expects to initiate a Phase 2 study of enoblituzumab in a chemo-free regimen in combination with either retifanlimab (an investigational PD-1 antibody) in front-line patients with SCCHN who are PD-L1 positive or with tebotelimab (an investigational PD-1 x LAG-3 bispecific DART^® antibody) in SCCHN patients who are PD-L1 negative. We expect to participate in a subsequent Phase 3 global study if and when initiated, as we deem appropriate. In addition, considering the dynamic regulatory environment and evolving clinical practice, we have been continually refining the development of enoblituzumab in our territory. Further clinical development may be planned together with MacroGenics to extend to other cancer indications in China and/or globally.

Eftansomatropin is a potentially highly differentiated long-acting human growth hormone that is being developed as a weekly treatment for pediatric growth hormone deficiency as compared to currently available daily regimens of recombinant human growth hormone (“rhGH”). Eftansomatropin was originally developed by Genexine, and we own the Greater China rights of this product, which has the potential to address an important clinical need and to cover a significant market gap in pediatric growth hormone deficiency. In a previous Phase 2 trial conducted by Genexine in South Korea and the EU, both weekly and bi-weekly administration of Eftansomatropin demonstrated similar therapeutic effects to daily injection of Genotropin, a short-acting rhGH. In September 2020, the NMPA approved our IND application for a registrational Phase 3 trial of eftansomatropin in pediatric growth hormone deficiency (PGHD). We expect to initiate this trial in the first quarter of 2021.

Highlights of Our Fast-to-PoC Global Portfolio

Our fast-to-PoC global strategy is demonstrated by our Global Portfolio, which mainly consists of our internally developed novel or differentiated biologics. Our Global Portfolio focuses on two molecular classes—monoclonal antibodies and bi-specific antibodies. While we have been diligently pursuing our fast-to-PoC global strategy, we are aware that there is no assurance that we will always be successful in achieving PoC or pivotal development milestones for any of our product candidates in our Global Portfolio in an accelerated manner. See “Risk Factors” for a detailed description of the risks related to the development and commercialization of our drug candidates.

Monoclonal antibodies—Among the five monoclonal antibody drug candidates, lemzoparlimab (TJC4), uliledlimab (TJD5) and plonmarlimab (TJM2) are in clinical development.

Lemzoparlimab is an internally discovered, fully human monoclonal antibody targeting CD47, which is one of the most promising immuno-oncology targets after PD-1/PD-L1. Blocking CD47 activates tumor-engulfing macrophages, a component of the innate immune system as an important cancer-fighting mechanism. CD47 antibodies are being actively pursued in clinical trials by a few global companies. However, current development efforts on CD47 antibody drugs are hampered by hematologic side effects (such as anemia) due to binding to human RBCs. For example, at least two clinical trials conducted by other companies have been suspended. Unlike competitor investigational drugs, lemzoparlimab is a rare antibody originally selected, by design, to purposefully avoid or minimize binding to RBCs while maintaining a high antibody affinity and tumor killing properties. Lemzoparlimab’s unique property of minimal RBC binding and no significant hematologic

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changes has been extensively validated in a whole series of robust in vitro assays and non-human primate studies. In a GLP toxicology study involving 40 monkeys, no hematologic side-effects were seen even with repeated injections of 100 mg/kg doses. This unique property may enable lemzoparlimab to be used safely in a broader patient population to explore its treatment potential in cancers, differentiating it from other clinical stage lemzoparlimab investigational antibody drugs. Notably, the topline results of the recently completed Phase 1a dose escalation monotherapy trial in the United States have demonstrated the differentiated profile of lemzoparlimab in drug safety and favorable pharmacokinetics in cancer patients. The key findings include: (i) lemzoparlimab was well tolerated up to 30 mg/kg on a weekly basis without priming dosing strategy, and no dose-limiting toxicity and no clinical or laboratory evidence of hemolytic anemia were observed throughout; (ii) lemzoparlimab PK appears to be linear at mid to high dose levels following a single dose with no significant “sink effect” and (iii) one confirmed Partial Response (PR) was observed in the 30 mg/kg cohort (N=3), and this patient had failed prior treatments with checkpoint inhibitors. Three patients achieved Stable Disease (SD). Therefore, we believe that lemzoparlimab, if approved, will be a potentially highly differentiated anti-tumor CD47 antibody with the advantage of minimizing hematologic side effects. In September 2020, we received the NMPA approval for a Phase 1 clinical trial of lemzoparlimab in relapsed or refractory advanced lymphoma in China as part of the ongoing international multi-center trial. In addition, lemzoparlimab is being evaluated in a Phase 1/2a clinical trial in China in patients with relapsed or refractory acute myeloid leukemia (r/r AML) or myelodysplastic syndrome (MDS), and we anticipate reporting top-line results in early 2021. We have also entered into a clinical trial collaboration and supply agreement with Merck Sharp & Dohme Corp, or MSD, through a subsidiary, under which we will sponsor a Phase 1 clinical trial in the United States evaluating lemzoparlimab in combination with KEYTRUDA^® (pembrolizumab), MSD’s anti-PD-1 therapy, in patients with multiple types of solid tumors. In September 2020, we granted AbbVie a global license, excluding Mainland China, Hong Kong and Macau, to develop and commercialize lemzoparlimab (as well as certain other compounds directed against CD47), and we will retain all rights to develop and commercialize lemzoparlimab in Mainland China, Hong Kong and Macau.

Uliledlimab is an internally developed, humanized inhibitory antibody against human CD73. CD73 is a homodimeric enzyme expressed in tumors and plays a critical role in suppressing immune cells in tumor micro-environment. Uliledlimab displays sub-nanomolar binding affinity to CD73 and inhibits its nucleotidase activity. In vitro, uliledlimab completely reversed the AMP- or tumor cell-mediated suppression of T cells. In vivo, when combined with a PD-L1 antibody, uliledlimab exhibited a superior or synergistic inhibitory effect on tumor growth. The key differentiation of uliledlimab when compared to some of the other clinical stage antibodies of the same class, is related to its novel epitope, which works through a unique intra-dimer binding mode, resulting in a complete inhibition of the enzymatic activity and avoiding the aberrant pharmacological property known as the “hook effect.” With this particular mode of action, uliledlimab, if approved, has the potential to become a highly differentiated CD73 antibody. We have completed the initial assessment of the clinical trial in the United States as a single agent and in combination with atezolizumab (TECENTRIQR), a PD-L1 antibody marketed by Roche, in patients with advanced solid tumors. Topline results from a clinical study under contract with TRACON show that uliledlimab is safe and well tolerated at the dose range evaluated and demonstrate clinical activity in patients with advanced solid tumors. We are scheduled to submit an abstract to ASCO for the 2021 annual meeting. In China, we are conducting a Phase 1/2 clinical trial to evaluate uliledlimab in patients with advanced solid tumors. The first patient in the single agent study was dosed in May 2020. The first patient in the combination study was dosed on February 3, 2021. This Phase 1/2 study is a multicenter, open-label, dose escalation and cohort expansion study, which will evaluate safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy of uliledlimab, and determine a recommended dose for further planned clinical studies of its efficacy and safety as a single agent and in combination with standard dose of toripalimab (TUOYIR) in patients with advanced or metastatic cancers who are refractory to or intolerant of all available therapies. We have been able to accelerate the Phase 1/2 trial in China by leveraging data from the ongoing Phase 1 clinical study of uliledlimab in the United States, which is a testament to our global clinical development capabilities and well-executed pipeline strategies.

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Plonmarlimab is an internally discovered neutralizing antibody against human granulocyte-macrophage colony-stimulating factor (“GM-CSF”), an important cytokine that plays a critical role in chronic inflammation and destruction in autoimmune diseases such as rheumatoid arthritis (“RA”). Plonmarlimab is a humanized IgG1 that displays high affinity binding to GM-CSF and blocks its signaling and downstream effects. Plonmarlimab is being developed for the treatment of autoimmune and inflammatory diseases, including RA and cytokine release syndrome (“CRS”). We have completed a single-dose first-in-human study in healthy volunteers in the United States. In China, plonmarlimab is the first antibody of its class entering clinical development. We dosed the first patient in a Phase 1b study of plonmarlimab in August 2020 in patients with rheumatoid arthritis (RA) in China. We may expand plonmarlimab to other autoimmune and inflammatory indications with high unmet medical need, where GM-CSF is known as a pathogenic cytokine in disease activity and progression. If approved, plonmarlimab is expected to provide an effective treatment option as a disease-modifying anti-rheumatic drug (“DMARD”) therapy. In addition, since the COVID-19 outbreak, we have sprung into action to prioritize plonmarlimab in response to the urgent medical needs. In May 2020, we announced preliminary results from part 1 of a clinical study in the United States of plonmarlimab in patients with cytokine release syndrome (CRS) associated with severe COVID-19, in which plonmarlimab was found to be well tolerated. We are currently conducting part 2 of this clinical trial to evaluate the efficacy, safety and cytokine levels following a single dose of 6 mg/kg plonmarlimab or placebo (standard care) in patients with severe COVID-19. We are currently in discussion with the FDA to finalize the plan for plonmarlimab in relation to clinical development and potential registration in the United States.

TJ210 is a novel monoclonal antibody directed at C5aR for cancers through a partnership with MorphoSys. In September 2020, the FDA has cleared the IND application for TJ210 to initiate a Phase 1 clinical trial. The trial is designed to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of TJ210 and is expected to commence by early 2021. We plan to work jointly with MorphoSys to develop this asset.

Bi-specific antibody panel—This novel antibody class represents an emerging and fast-moving area of new drug discovery. Bi-specific antibodies are typically constructed to have a dual specificity of two selected antibodies or combined properties of an antibody linked with a cytokine, previously called an immune-cytokine. However, despite the recent success of checkpoint inhibitors, clinical efficacy of these drugs has been unsatisfactory. It is estimated that over 60% of cancer patients, including those with melanoma, renal cell cancer, colorectal cancer, non-small cell lung cancer, urothelial cancer and head and neck squamous cell carcinoma, do not respond to PD-1/PD-L1 monotherapies. In addition, some patients develop resistance after initial treatment with these therapies. As a result, the standard of care today leaves many cancer patients underserved. There is consensus among cancer immunologists that tumors that do not respond to PD-1/PD-L1 treatment have poor immunologic features, such as an absence or paucity of tumor-fighting immune cells or the presence of dysfunctional immune cells within the tumors, collectively known as “cold tumors.” We believe that PD-1/PD-L1 non-responders can be better treated with novel bi-specific antibodies. The unique and superior properties of these bi-specific antibodies over PD-L1 inhibitors alone stem from a second targeting component attached to the PD-L1 antibody moiety of the bi-specific molecules, thereby enabling them to elicit a sufficient immune response and converting a “cold tumor” to an immune-active “hot tumor.” Such unique properties of bi-specific antibodies cannot be substituted by a combination of the PD-L1 antibody with a selected second component (either cytokine or antibody) in a free form. The underlying mechanism is such that the second component must be structurally integrated with the tumor-engaging PD-L1 antibody in order to concentrate and function inside the tumor, which cannot be readily achieved by the two free agents used in combination.

We have successfully generated a panel of bi-specific antibodies in which our proprietary PD-L1 antibody acts as the backbone (the first signal) and is linked with various second components (the second signal), including, but not limited to, a 4-1BB agonist antibody (TJ-L14B), a B7-H3 antibody (TJ-L1H3), a CD47 antibody (TJ-L1C4) and an IL-7 cytokine (TJ-L1I7), which are shown to work with the PD-L1 backbone in various assays and cancer animal models. This unique panel of bi-specific antibodies is only made possible by our proprietary and partnered antibody engineering technologies and the availability of our proprietary monoclonal antibodies. Furthermore, we have generated two other bi-specific antibodies (TJ-C4GM and

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TJ-CLDN4B) that are tailor-made to function as novel fortified antibodies by linking lemzoparlimab with an engineered GM-CSF cytokine for the treatment of solid tumors and by linking our Claudin 18.2 antibody with a 4-1BB antibody as a unique gastric cancer treatment agent that only activates T cells conditionally upon tumor engagement. All bi-specific antibodies have been validated in a series of robust in vitro and in vivo studies for biology proof-of-concept, providing a solid basis for clinical validation in cancer patients.

Our Strategies

Moving forward, we strive to become a fully integrated end-to-end global biopharmaceutical company whose capabilities encompass drug discovery, GMP manufacturing, pre-clinical and clinical development and commercialization. To achieve this goal, we intend to pursue the following strategies.

Rapidly advance our China Portfolio towards commercialization

We intend to pursue the most efficient pathway to NDA approval for the investigational drugs in our China Portfolio. In the next 12 months, we expect to make significant advances with our China Portfolio. Most of the clinical assets of our China Portfolio are expected to undergo Phase 2, Phase 3 or registrational clinical trials in 2021. We plan to submit NDAs to the NMPA for our China Portfolio products in sequence from 2021 to 2024. With respect to commercialization capabilities, we plan to initially partner with a specialty pharmaceutical company that has existing commercial capabilities and infrastructure in China to jointly market our leading products. Once we have acquired commercial experience and developed a distribution network, we plan to build a robust internal sales and marketing platform.

Expand our research and development capabilities and footprint in the United States to advance our Global Portfolio

As part of our global strategy, we plan to expand our research and development capabilities in the United States to include regulatory affairs, translational medicine, drug formulation and clinical operations. These specific research and development functions in the United States are complementary to and an integral part of our overall research and development capabilities to support clinical development of our Global Portfolio. Currently, three of our investigational antibody drugs (lemzoparlimab, uliledlimab and plonmarlimab) are in clinical trials in the United States. We aim to continue advancing the ongoing clinical trials to Phase 2 for clinical validation and to initiate multiple new clinical programs by 2022 in the United States. In addition, we intend to expand our operational footprint in the United States to create an independent multi-functional business entity covering global business development, investor relations and corporate communications and other operational capabilities. We are in the process of assembling an integrated management team with global experience and extensive track record dedicated to overseeing our operations in the United States.

Build our manufacturing capabilities

We believe it is strategically important and advantageous that we own and control our GMP manufacturing process in order to ensure quality, secure production slots and maximize cost-effectiveness for clinical trial materials and commercial supplies. We intend to build a comprehensive biologics manufacturing facility in Hangzhou, China (the “Hangzhou Facility”) as part of our strategic plan to become a fully integrated biopharma company. We have taken concrete steps to execute this plan. These steps include detailed operational planning for the facility, actions taken to secure an appropriate site, and negotiations with external financing providers. The Hangzhou Facility targets to have a pilot capacity of 2 production lines (1 line configured with 2 x 2,000L and another line with 1 x 2,000L) by the end of 2021 and commercially progressive capacity up to 8 x 4,000L to begin operation by the end of 2023. Construction is expected to commence in April 2021 and ready for use by the end of 2023. The project will be financed by a combination of internal and external sources. In September 2020, a group of domestic investors in China invested a total of US$120 million (in RMB equivalent) in cash. Upon closing, I-Mab Hangzhou became an affiliate of us. We, through our wholly owned subsidiary and parties acting

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in concert, remain the majority shareholder of I-Mab Biopharma (Hangzhou) Limited (“I-Mab Hangzhou”), the entity holding the Hangzhou Facility, and retain a managing role and take full control to build and operate the manufacturing facility. We plan to prioritize our therapeutic focus and resources on immuno-oncology in our global ambition to become a leading immuno-oncology company. This goal has been accelerated by our recent global strategic collaboration with AbbVie and its commercialization plan for the initial oncology products. I-Mab Hangzhou is positioned to provide manufacturing capabilities for us, as well as the continued development of selected biologics assets that are non-essential to our immuno-oncology focus, i.e. olamkicept, plonmarlimab (excluding cytokine release syndrome indications) and a few pre-clinical CMC-stage programs. We believe that this strategic alignment is necessary to maximize the pipeline value and balance the development risk for us.

Maximize the value of our pipeline

In addition to our successful in-licensing efforts, we have established a good track record of out-licensing collaborations and co-development partnerships. For the years ended December 31, 2017, 2018 and 2019, we recorded revenues of RMB11.6 million, RMB53.8 million and RMB30.0 million from upfront and milestone payments through three out-licensing deals, respectively. We have reached cost-sharing co-development deals for some of our drug candidates with multiple global and regional partners. In September 2020, we, through I-Mab Biopharma Co., Ltd. and I-Mab Biopharma US Limited, each a wholly-owned subsidiary of our company, entered into a broad global strategic collaboration with AbbVie Ireland Unlimited Company (“AbbVie”), a leading global, research-based biopharmaceutical company. Pursuant to this collaboration, we grant AbbVie an exclusive global license, excluding Mainland China, Hong Kong and Macau, to develop and commercialize lemzoparlimab (as well as certain other compounds directed against CD47). We retain all rights to develop and commercialize lemzoparlimab in Mainland China, Hong Kong and Macau. Pursuant to this collaboration, AbbVie has paid us an upfront payment of US$180 million. Additionally, in connection with the recently released clinical data from the Phase 1 trial of lemzoparlimab in the United States, we expect to be paid a first milestone payment of US$20 million. We will also be eligible to receive up to US$1.74 billion in further success-based development, regulatory and sales milestone payments for lemzoparlimab, of which US$840 million are based on clinical development and regulatory approval milestones, with the remainder based on commercial milestones. Upon commercialization of lemzoparlimab, AbbVie will also pay tiered royalties consisting of low double-digit percentages on global net sales outside of Mainland China, Hong Kong and Macau. In addition, AbbVie has a license and a right of first negotiation to further develop and commercialize two additional lemzoparlimab-based bispecific antibodies discovered and currently being developed by us, and we cannot commercialize products containing these two additional lemzoparlimab-based bispecific antibodies outside of Mainland China, Hong Kong and Macau even if AbbVie does not exercise its right of first negotiation or we are unable to come to financial terms on such products. The potential value of each such license is minimum US$500 million in upfront and milestone payments, for a combined total of no less than US$1 billion.

These achievements, in particular our collaboration with AbbVie, have not only demonstrated our ability to optimize our pipeline but also provided a sustainable revenue stream. Going forward, we plan to enhance our out-licensing efforts. We expect that the revenue generated from out-licensing opportunities will continue to increase and will account for the majority of our net revenue before the commercialization of our marketed products.

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Our Drug Pipeline

China Portfolio

Felzartamab (TJ202): A Potential Highly Differentiated CD38 Antibody for Multiple Myeloma and Autoimmune Diseases

Summary

Felzartamab is a fully human, highly differentiated monoclonal antibody directed against CD38. Felzartamab, if approved, is positioned as a potential highly differentiated anti-CD38 therapy for multiple myeloma (“MM”), either as a monotherapy or as a combination therapy with other anti-cancer agents. We aim to demonstrate the advantages of felzartamab, including its short infusion time, low infusion related reaction (“IRR”) and potentially sustained efficacy, in our ongoing clinical trials in China. Additionally, as pathogenic CD38-positive B cells and plasma cells are strongly implicated in the disease progression of pathogenic antibody-mediated autoimmune diseases, we believe the therapeutic value of felzartamab can be extended to these diseases that have significant unmet medical needs. We have begun to explore its therapeutic application in systemic lupus erythematosus (“SLE”) and later in other autoimmune diseases. In November 2017, we obtained an exclusive license from MorphoSys to develop felzartamab in Greater China. The development of felzartamab is driven by a fast-to-market strategy. We are conducting two parallel registrational trials with felzartamab as a third-line monotherapy and as a second line combination therapy with lenalidomide, both in patients with multiple myeloma in Greater China. The recruitment progress for these two trials remains on track, and we expect to submit an NDA to the NMPA in 2021. Additionally, we submitted an IND application to the NMPA in October 2019 for a Phase 1b trial for felzartamab in SLE.

Therapeutic Options and Current Development

Multiple Myeloma (MM)

The treatment options and investigational drugs under development in China include: (i) for small molecule drugs, two or three approved drugs known as doublets or triplets are used. VRD triplet (Velcade (bortezomib), Revlimid (lenalidomide) and dexamethasone) has been approved for overseas frontline treatment and is recommended in China in the 2017 version of treatment guideline. VCD triplet (Velcade, cyclophosphamide and dexamethasone) is the most widely adopted first-line treatment in China due to its lower cost. In 2017, lenalidomide and bortezomib were included in the National Reimbursement Drug List in China; (ii) with respect to CD38 antibody therapy, daratumumab (from Johnson & Johnson) received conditional NDA approval from the NMPA in July 2019, and isatuximab (from Sanofi) is in a Phase 3 trial in China; and (iii) for CAR-T therapy, several Phase 1 or 2 clinical trials are ongoing in China.

However, there is no curative treatment for MM. Although the currently marketed CD38 antibody (daratumumab) in China is efficacious, it takes a long time to be administered by IV infusion (up to six hours) and causes a high infusion reaction rate (“IRR”). In clinical trials, approximately half of all patients experience an infusion reaction, symptoms of which may include fever, chills, nausea, bronchospasm, hypoxia, dyspnea, hypertension, laryngeal edema and pulmonary edema. Thus, there is a need for a safer and convenient-to-use drug. Such a drug may be combined with other therapeutic agents for better treatment effects in MM.

Systemic Lupus Erythematosus (SLE)

Patients with mild SLE are often given non-steroidal anti-inflammatory drugs, while more severe patients may need corticosteroids or immunosuppressants. Approved by the FDA in 2011 and by the NMPA in July 2019, Benlysta (belimumab), a B-lymphocyte stimulator (BLyS)-specific inhibitor developed by GSK, is currently the world’s only biologic approved to treat SLE. However, there remains a significant unmet medical need beyond

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belimumab for SLE in China and the rest of the world. As dysregulated CD38-positive B cells and auto-antibodies produced by CD38-positive plasma cells and resulting immune complexes are at the core of the pathogenesis of SLE, direct inhibition and selective depletion of pathogenic B cells and plasma cells are believed to offer better treatment options. Our felzartamab has the potential to offer such a disease-modifying treatment option. In addition, as described below, the advantages of our felzartamab include convenience of use and a lower IRR, making it a more favorable treatment agent in the long-term clinical management of SLE if approved.

Advantages of Felzartamab

Felzartamab, if approved, is a potentially highly differentiated CD38 monoclonal antibody and could be the second antibody therapy for MM to launch in China. A Phase 2a trial of felzartamab in MM showed a level of treatment effects comparable to that observed in trials of the currently marketed CD38 antibody. However, available trial data from MorphoSys and Johnson & Johnson indicate that with similar pre-medications of dexamethasone, anti-pyretics and anti-histamines, Felzartamab required only a short infusion time of 0.5 to 2 hours, compared to 3.5 to 6.5 hours for the currently marketed CD38 antibody at the first infusion. Moreover, the IRR was as low as 7% for felzartamab, compared to 48% for the currently marketed CD38 antibody. The advantages of felzartamab associated with infusion may be attributed to its lack of antibody CDC activity and are likely to translate into clinical benefits in terms of tolerability and convenience of use as well as economic benefits due to the cost and length of hospital stay. In addition, unlike the currently marketed CD38 antibody, felzartamab treatment does not down-regulate CD38 expression on the surface of bone marrow myeloma cells in vitro, maintaining sensitivity of malignant myeloma cells to repeated felzartamab treatments. As felzartamab is being considered for long-term treatment management of autoimmune diseases, we believe such clinical differentiation is critical.

For autoimmune diseases, felzartamab has advantages over other B cell-targeting therapies such as CD20 antibodies, as it specifically targets malfunctioned CD38^high B cells and pathogenic plasma cells involved in autoimmune diseases while CD20 antibodies target most B cells, including those involved in normal immune functions and regulatory functions, but not plasma cells producing pathogenic antibodies.

Mechanism of Action

Felzartamab binds to CD38 overexpressed on the surface of target cells and kills them by inducing antibody-dependent cellular cytotoxicity (“ADCC”) and antibody-dependent cellular phagocytosis (“ADCP”). The target cells are the malignant plasma cells in MM and a group of dysregulated CD38^high B cells and plasma cells that produce pathogenic antibodies in autoimmune conditions such as SLE.

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Summary of Clinical Results

MorphoSys has conducted a Phase 1/2a study in adult patients with relapsed or refractory MM in Austria and Germany.

Study Design. The open-label, multicenter, dose-escalation study was designed to characterize the safety profile and preliminary efficacy of felzartamab in adults with relapsed or refractory MM. A 3+3 dose escalation design was used to establish the maximum tolerated dose (“MTD”), recommended dose and dosing regimen of felzartamab as monotherapy, weekly or bi-weekly, with or without dexamethasone (“DEX”), and in combination with pomalidomide (“POM”) and DEX or lenalidomide (“LEN”) and DEX standard regimens. The MTD and recommended dose and dosing regimens were to be confirmed in three confirmation cohorts of at least six evaluable subjects each. Felzartamab dose levels in this study ranged from 0.01 mg/kg to 16.0 mg/kg, administered by intravenous (“IV”) infusion.

The clinical study results as of the data cutoff date, December 31, 2017, are summarized as follows.

Safety. Felzartamab was well tolerated in patients with RRMM, as a single agent and in combination with DEX, or with POM/DEX, or with LEN/DEX. The MTD of felzartamab was not reached. In the 56 patients from three groups receiving combination regimens, grade ³ 3 adverse events (“AEs”) were mainly in the hematological system reflected by a decrease of various blood cells. This was as expected, because of decreased bone marrow function due to the presence of myeloma as well as the expression of CD38 on various cell lineages of the myeloid and lymphoid compartments. Most of the hematological adverse events were transient and generally manageable.

Felzartamab was administered as a two-hour IV infusion at first dose and infusion time could be reduced to as short as 30 minutes at subsequent doses without obvious safety concerns. Among all cohorts, infusion-related reactions, including tachycardia, pyrexia and hypersensitivity, occurred in 18 of 91 patients (19.8%) and were mostly mild to moderate. In the combination cohorts containing DEX, a very low IRR (4 out of 56 patients (7%)) was observed. These results compared favorably with the historical data of the currently marketed CD38 antibody.

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Clinical Efficacy. Preliminary efficacy results were based on 56 patients from three groups treated with felzartamab combination therapies. No responses were observed for the monotherapy groups which were primarily serving for dose escalation. Felzartamab in combination with low dose DEX, POM/DEX or LEN/DEX demonstrated an overall response rate (“ORR”) of 28%, 48% and 65%, respectively. Durable responses were observed as median progression-free survival (“PFS”) was of 8.4 months and 17.5 months for the DEX and the POM/DEX combination groups, respectively, and PFS levels were not reached for the LEN/DEX combination group, as there were not sufficient events of progression recorded.

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The definitions of PD, SD, MR, PR, VGPR, CR and sCR and how these responses were measured for multiple myeloma are set forth in the table below. (Source: International Myeloma Working Group Uniform Response Criteria (2006) and European Group for Blood and Marrow Transplantation Criteria)

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Pharmacodynamics. As a pharmacodynamic marker, serum myeloma (M) protein levels were used to evaluate severity and clinical response. The median relative change in M protein levels from baseline to post-baseline nadir for felzartamab in combination with low doses of DEX, POM/DEX or LEN/DEX was -13%, -58% and -81%, respectively. The data below show strong effects of felzartamab in reducing M protein levels.

Pharmacokinetics (“PK”). The PK of felzartamab in humans was well characterized by a two-compartment model at dose levels greater than 4 mg/kg. At these doses, stable or even increasing trough levels could be observed over time suggesting the potential for full target occupancy, especially at the highest dose level (16 mg/kg). For most subjects, steady state at 16 mg/kg was observed after the fourth infusion. Terminal half-life at high-dose levels (³ 4 mg/kg) was at approximately two weeks. Pharmacokinetics of felzartamab were generally consistent across different individuals and dosing days and not affected by the co-medications.

Immunogenicity. No anti-drug antibody (“ADA”) against felzartamab was observed as of the cut-off date. Thus, risk of ADA induction for felzartamab in humans is considered low.

Clinical Development Plan

Immediately after in-licensing felzartamab, we formulated a robust clinical development strategy with an aim for an NDA submission in 2021. With an approved IND, we have started a single-arm registrational trial with felzartamab and DEX as a third-line therapy for MM patients in Greater China using ORR as the primary endpoint (NCT03860038). Dosing of the first patient took place in March 2019. Data from this study are expected to be the major package supporting registrational filing in 2021 for conditional approval. In parallel, we started a registrational trial combining felzartamab with LEN and DEX as a second-line combination therapy in

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MM patients (NCT03952091). We plan to enroll 291 patients for full approval. Dosing of the first patient took place in Taiwan in April 2019. As of September 30, 2020, we had enrolled a total of 159 patients for these two registrational trials.

Our clinical development plan for SLE starts with a Phase 1b clinical trial to explore dose range, clinical safety and tolerability as well as felzartamab’s profiles of PK and pharmacodynamics (“PD”) in SLE patients. For this, we submitted an IND application to the NMPA in October 2019.

Efineptakin (TJ107): The First Long-acting Recombinant Human IL-7 with the Potential for Cancer Treatment-related Lymphopenia and Cancer Immunotherapy

Summary

Efineptakin is the world’s first and only long-acting recombinant human interleukin-7 (“rhIL-7”), which is being developed as a T lymphocyte-booster for cancer-related immunotherapy. Due to its advantages in terms of selective immune functions, improved stability, developability, and extended half-life, efineptakin is differentiated from an earlier generation of short-acting rhIL-7 and T cell growth factor (interleukin-2). In December 2017, we acquired exclusive rights from Genexine to develop and commercialize efineptakin in Greater China. We plan to position efineptakin first as a monotherapy or an oncology care product for cancer patients with cancer treatment-related lymphopenia (low blood lymphocyte levels) induced by chemotherapy or radiation therapy. This target indication covers a large population of cancer patients who develop cancer treatment-related lymphopenia, a condition that weakens the ability to receive continued chemotherapy or radiation therapy and leads to worsened disease prognosis and clinical outcome. Currently, there is no treatment available for this condition. Second, efineptakin is expected to show a therapeutic effect as a combination therapy with immune checkpoint inhibitors, i.e., PD-1/PD-L1 therapies, due to its inherent selective T cell-boosting properties. Pre-clinical studies have indicated that efineptakin exerted additional anti-tumor effect when combined with PD-1/PD-L1 therapies. If proven efficacious in clinical studies, we believe such a combination therapy, can potentially treat a large population of cancer patients who do not respond or respond poorly to PD-1/PD-L1 therapies. In May 2020, we obtained regulatory clearance from the NMPA to initiate a Phase 2 clinical trial in GBM patients with lymphopenia. We had the first patient in on December 31, 2020 and the first patient dosed on February 4, 2021.

Therapeutic Options and Current Development

One of the target therapeutic indications of efineptakin is cancer treatment-related lymphopenia. Cancer patients who undergo chemotherapy and/or radiation therapy often develop cancer treatment-related lymphopenia, which further damages their already compromised immune systems and their ability to fight against cancers. Advanced solid tumor is another indication of efineptakin as a combination therapy with PD-1/PD-L1 treatments. As more than 60% cancer patients either do not respond or respond poorly to current PD-1/PD-L1 therapies, there are intense attempts to identify an effective agent that can work synergistically with PD-1/PD-L1 therapies to increase the probability of treatment success. Efineptakin is believed to provide such a treatment option, which is supported by pre-clinical reports that IL-7 exhibits a synergistic effect with PD-1/PD-L1 antibodies in the treatment of cancers.

Advantages of Efineptakin

Efineptakin has an advantage over other T lymphocyte cytokines with therapeutic potential in oncology. Pre-clinical and clinical results generated so far indicate that efineptakin has a favorable immune function profile over recombinant human interleukin-2 (“rhIL-2”) in that efineptakin activates and expands tumor-fighting CD4, CD8 and natural killer T cells but spares tumor-protecting Treg cells. By contrast, rhIL-2 is a well-known inducer of Tregs, which suppresses tumor-fighting effector T cells. Furthermore, rhIL-2 has a narrow therapeutic window and causes serious side effects such as capillary leak syndrome, breathing problems, serious infections, and

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seizures. A polyethylene glycol (PEG)-conjugated IL-2 variant developed by Nektar Therapeutics has yielded mixed results, indicating the complexity associated with using IL-2 as a cancer treatment. Owing to its preferred immune function and molecular profiles demonstrated in pre-clinical and Phase 1/2 clinical trials, we believe that efineptakin is a superior T cell cytokine investigational drug for cancer treatment-related lymphopenia and cancer immunotherapy.

Efineptakin, as an engineered rhIL-7, has the advantages of improved stability and half-life extension through Genexine’s proprietary hybrid fragment crystallizable region (“hyFc”). Introducing a few hydrophilic amino acid residues to the N-terminus of IL-7 overcomes stability issues that hampered the development of previous rhIL-7 drug candidates. Furthermore, application of the hyFc technology enhances IL-7’s function, increases its half-life (from 48 to 112 hours after a single subcutaneous (“SC”) dose in clinical studies), and allows for a robust purification process. By contrast, the half-life of first-generation rhIL-7 was reported to be about 12 hours after SC dosing in human subjects. The hyFc in efineptakin is also non-cytolytic, so it will not damage the T cells to which it binds. Unlike efineptakin, the previous rhIL-7 drug candidates adopt non-glycosylated (CYT 99-007) or glycosylated (CYT-107) forms of short-acting rhIL-7 and were developed by Revimmune Inc (formerly known as Cytheris SA). These molecules had low stability, low production yield, and a short half-life because IL-7 protein is intrinsically unstable and prone to aggregation. However, the preliminary clinical results from Phase 1 and Phase 2 trials in patients with AIDS did show an increase of T lymphocytes following treatment with CYT-107 (Thiebaut R et al., PLoS Comput Biol., 2014).

Mechanism of Action

IL-7 is a cytokine essential for the survival and homeostatic proliferation of naive and memory T cells (see figure below). IL-7 is critically involved in restoring T cells to normal levels in the event of lymphopenia by stimulating T cell proliferation. IL-7 exerts its functions by binding to and activating the IL-7 receptor, which is expressed primarily on lymphocytes, including the lymphoid precursors, developing T and B cells, naive T cells, and memory T cells, but not on tumor-protecting Tregs. Efineptakin as a monotherapy may enhance anti-tumor immunity by augmenting the number and functionality of T cells, whereas efineptakin in combination with an immune checkpoint inhibitor, cancer vaccine or CAR-T may improve the anti-tumor response by restoring T cell numbers, reconstituting T cell pools and reinvigorating exhausted T cells.

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Summary of Clinical Results

A first-in-human Phase 1 trial has been conducted by Genexine in South Korea. This was a randomized, double-blind, placebo-controlled, single ascending dose study, to evaluate the safety, tolerability, pharmacokinetic and pharmacodynamic properties of 20 or 60 µg/kg efineptakin via SC or intramuscular (“IM”) administration in healthy volunteers. Each dose group consisted of 10 subjects, eight of whom were administered efineptakin and two were given placebo via the same route of administration.

Safety. Efineptakin was well-tolerated in all 30 subjects without serious adverse events. The most common adverse events were transient Grade 1 or 2 injection site skin reactions.

Pharmacodynamics (“PD”). Because IL-7 promotes the survival and proliferation of T cells, absolute lymphocyte count (“ALC”) in the peripheral blood was used as a reliable and convenient PD marker for efineptakin (see figure below). ALC initially decreased transiently in all efineptakin groups. This effect is often termed margination, which is a physiological phenomenon common to many cytokines as a result of increased adherence of cytokine-stimulated white blood cells to the blood vessels and subsequent trafficking to tissues and lymphoid organs. ALC recovered in approximately seven days, reaching a maximum value at close to 21 days, before gradually declining. This result indicated that a single dose of efineptakin had a long-lasting effect of increasing lymphocyte levels. Overall, a greater increase in ALC was observed in Cohort 2 compared with Cohort 1, demonstrating a dose-dependent response. Additionally, a higher increase in ALC was observed in Cohort 3 compared with Cohort 2, which was consistent with the results of an animal study, where IM injection induced a more effective increase in lymphocytes than SC injection.

Efineptakin treatment resulted in a substantial increase in the number of CD4 and CD8 T cells, natural killer T cells, naive T cells, central memory, effector memory, and terminally differentiated effector memory T cells, without affecting the number of B cells, natural killer cells, monocytes or Tregs.

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Pharmacokinetics. Efineptakin was slowly absorbed, particularly after SC administration, and was slowly removed, resulting in a half-life of 48 to 112 hours, longer than that reported for the first generation rhIL-7 (about 12 hours). Intramuscular efineptakin showed approximately two-fold greater exposure than SC administration at the same dose level of 60 µg/kg. The higher plasma exposure of efineptakin after IM administration was well-correlated with a more robust PD effect on ALC in Cohort 3.

Immunogenicity. ADAs were detected in 22 of 24 subjects treated with efineptakin. One subject in Cohort 3 was positive for ADAs before treatment. Neutralizing antibodies were observed in 42% and 46% of the subjects within one to two months following administration, respectively, but only one person still harbored neutralizing ADAs five months after administration.

The clinical relevance of ADA was evaluated during long-term follow-up monitoring. ALC levels were maintained above the baseline values, endogenous IL-7 was maintained at normal levels, and no specific adverse events associated with ADAs were observed. These results are consistent with well-documented reports that a normal individual can harbor pre-existing auto-antibodies for cytokines such as IL-2, IL-3, IL-4, and IL-7, and that these anti-cytokine antibodies tend to serve as a reservoir and carrier of the cytokines in the blood, extending the half-life of these cytokines and preserving their functions.

Clinical Development Plan

By leveraging the results of Genexine’s ongoing clinical trials in South Korea and the United States, we aim to rapidly advance the clinical development of efineptakin for approval in Greater China. Currently, a Phase 1b trial in China is ongoing to investigate the safety, tolerability and PK/PD response of efineptakin in patients with advanced solid cancers. The clinical trial (NCT04001075) is designed to include: (i) dose escalation of efineptakin using a conventional “3 + 3” study design to identify a safe and active dose range and (ii) dose expansion to confirm the safety and obtain preliminary evidence of efficacy. We have finished dose escalation for the four dose cohorts, and the safety and tolerability profile as well as the PK/PD response are consistent with other ongoing studies of efineptakin.

We have obtained regulatory clearance from the NMPA to initiate a Phase 2 clinical trial in GBM patients with lymphopenia. We had the first patient in on December 31, 2020 and the first patient dosed on February 4, 2021. In addition, Genexine and we intend to expand our collaboration, where we will be mainly responsible for conducting the Phase 2 clinical trial in China, and Genexine will share the development strategies, data and costs for success of this clinical trial.

Genexine has initiated a dose-finding trial in combination with checkpoint inhibitors in patients with solid tumors. Meanwhile, Genexine is also sponsoring additional early-stage clinical trials in advanced solid tumors,

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including glioblastoma and high-risk skin cancer, in the United States and South Korea. The safety, pharmacology and preliminary efficacy data from these ongoing studies are expected to significantly facilitate our clinical development of efineptakin in Greater China.

Eftansomatropin (TJ101): A Potential Highly Differentiated Long-Acting Growth Hormone for Growth Hormone Deficiency

Summary

Eftansomatropin, if approved, is a potential highly differentiated long-acting recombinant human growth hormone (“rhGH”) being developed as a more convenient and effective therapy for growth hormone deficiency (“GHD”), for which there is substantial unmet medical need in China. Eftansomatropin met the pre-set safety endpoints in three multi-regional clinical trials conducted in Europe and Asia and preliminary efficacy endpoints in pre-pubertal growth hormone naive pediatric growth hormone deficient (“PGHD”) patients. In contrast to marketed short-acting rhGH such as Genotropin, eftansomatropin showed similar efficacy results in a weekly (vs. daily) regimen. Furthermore, eftansomatropin has not shown the safety concerns typically associated with approved pegylated drugs. We in-licensed the China rights to eftansomatropin from Genexine and are positioning eftansomatropin as a highly differentiated growth hormone replacement therapy because of its advantages over a daily regimen in terms of injection frequency (weekly vs. daily) and safety profile (natural protein-based vs. pegylated long-acting rhGH), especially in pediatric patients. In September 2020, the NMPA approved our IND application for a registrational Phase 3 trial of eftansomatropin in pediatric growth hormone deficiency (PGHD). We expect to initiate this trial in the first quarter of 2021.

Therapeutic Options and Current Development

Our current therapeutic indication is PGHD. The widely adopted treatment for PGHD is patient-specific growth hormone replacement therapy, which is given in a calculated weight-based dosing regimen. Currently, short-acting recombinant human growth hormone (“rhGH”) is commonly used for the long-term treatment of children and adults with inadequate endogenous growth hormone secretion. There are certain safety concerns related to long-term use of pegylated drugs, such as potential renal toxicity, cellular vacuolation and formation of anti-polyethylene glycol antibodies. Approved by the NMPA in 2014, Jintrolong (developed by GeneScience) is currently the only marketed long-acting pegylated rhGH in China. Other companies in China currently developing long-acting rhGH include Anhui Anke Biotechnology, Xiamen Amoytop Biotech, Generon Pharmaceutical Technology and Visen Pharmaceuticals. Our eftansomatropin is the only Fc-based long-acting rhGH ready for a Phase 3 clinical trial in China.

Only a very small portion of all PGHD patients in China were receiving growth hormone replacement therapy in 2018, which primarily consists of daily injections of rhGH before sleep. This dosing regimen puts a substantial burden on pediatric patients and their families because it requires drug preparation and needle injection every day, which is painful and extremely inconvenient, often resulting in poor patient compliance. More importantly, studies have shown that skipping just one or two doses in a week can markedly reduce the efficacy of the treatment. Therefore, there is a substantial unmet medical need for long-acting growth hormone therapies that are similarly efficacious but with reduced injection frequency, and the market potential for such a long-acting rhGH in China is largely untapped. In addition, recombinant human growth hormone therapy has been included in the National Reimbursement Drug List (NRDL) in China. Inclusion of a drug in the NRDL typically results in a much higher sales volume and significant sales growth despite a reduction in price.

Advantages of Eftansomatropin

We believe that eftansomatropin has the following advantages: (i) when compared to the daily regimen of rhGH, eftansomatropin is expected to be a more convenient therapy with better patient compliance due to a reduced dosing frequency to either weekly or twice-monthly administration, while maintaining similar efficacy;

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and (ii) eftansomatropin has not shown safety concerns typically associated with pegylated drugs, such as potential renal toxicity, pre-existing or treatment-induced anti-PEG antibodies, and cellular vacuolation in macrophages, renal tubule cells and the choroid plexus epithelial cells.

Mechanism of Action

Like endogenous growth hormone, eftansomatropin stimulates the production of insulin-like growth factor 1 (“IGF-1”) in the liver, which has growth-stimulating effects on a variety of tissues, including osteoblast and chondrocyte activities that stimulate bone growth. Thus, IGF-1 is a reliable pharmacodynamic marker and more importantly, the key mediator of eftansomatropin’s growth-promoting activity. Eftansomatropin is based on Genexine’s patented hyFc technology. The hyFc part consists of a portion of human immunoglobulin D (“IgD”) and G₄ (“IgG₄”). The former contains a flexible hinge, and the latter is responsible for half-life extension through neonatal Fc receptor (“FcRn”)-mediated recycling. Additionally, eftansomatropin’s increased molecular weight (103 kilodalton) is expected to reduce renal clearance.

Summary of Clinical Results

Genexine has completed three clinical trials with eftansomatropin, including one Phase 1 trial in healthy adult volunteers, one Phase 1b/2 multi-regional trial in adults with GHD, and one Phase 2 multi-regional trial in PGHD in Europe, altogether involving 32 healthy subjects and 99 patients with GHD and PGHD. Overall, eftansomatropin was shown to be well-tolerated, and clinical efficacy endpoint achieved by weekly or twice-monthly eftansomatropin administration was comparable to that of daily administration of Genotropin.

Phase 1 Clinical Trial

The first-in-human trial of eftansomatropin was a randomized, double-blind, placebo-controlled single dose-ascending study in four groups of healthy subjects. A total of 32 subjects were enrolled, and 31 completed the study. Eftansomatropin was shown to be well-tolerated at all dose levels studied (0.2–1.6 mg/kg). Eftansomatropin was detectable in the blood until Day 7 for the 0.2 mg/kg dose group, Day 14 for the 0.4 and 0.8 mg/kg dose groups, and Day 21 for the 1.6 mg/kg dose group. A single subcutaneous (“SC”) injection of eftansomatropin at dose levels of 0.4 mg/kg and higher increased IGF-1 and IGF-binding protein-3 (“IGFBP-3”) levels for at least one week. No safety concerns were identified. Eftansomatropin showed a half-life ranging from 69.2 to 138 hours.

Phase 2 Clinical Trial in PGHD

Study Design. The Phase 2 trial in PGHD was a randomized, open-label, active-controlled study to assess the safety, tolerability, efficacy, pharmacokinetics, and pharmacodynamics of weekly and twice-monthly doses of eftansomatropin, as compared to a daily injection of Genotropin, which is currently the standard of care for

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PGHD. Subjects were randomly assigned to receive one of three doses of eftansomatropin (0.8 mg/kg/weekly, 1.2 mg/kg/weekly or 2.4 mg/kg/twice monthly) or 0.03 mg/kg/daily of Genotropin for up to 24 months. The primary clinical endpoint was annualized height velocity (aHV) in centimeters (cm) per year (equivalent to annual growth rate), measured at six months. A total of 56 subjects were randomized at 27 centers in nine European countries and South Korea. Fifty-two subjects completed the six-month treatment (through Visit 7), meeting the primary endpoint. Two subjects withdrew from the study before first drug administration, and two subjects discontinued due to treatment-related adverse events (“AEs”). Genexine and its co-developer Handok presented the latest interim results of the Phase 2 clinical trial for PGHD in March 2018 at the Endocrine Society’s annual meeting.

Safety. No study drug-related serious adverse events (“SAEs”) or death were observed. The tolerability of eftansomatropin was consistent with known properties of marketed products. The AE incidence rate was generally similar across the eftansomatropin cohorts treated with three different dose levels (ranging between 69.2% and 84.6%) and the Genotropin cohort (57.1%). A total of two (14.3%), three (23.1%), two (15.4%), and zero subjects experienced treatment-related AEs in the 0.8 mg/kg/week, 1.2 mg/kg/week, and 2.4 mg/kg/twice monthly eftansomatropin groups, and the 0.03 mg/kg/daily Genotropin group, respectively.

Two subjects withdrew from the study due to treatment-related AEs. One subject from Cohort 2 (1.2 mg/kg/week of eftansomatropin) discontinued due to retinal vascular disorder. The Data and Safety Monitoring Board (“DSMB”) reviewed this case independently, concluding that the retinal finding was more likely to be of completely different etiology than treatment-induced intracranial hypertension. One subject from Cohort 3 (2.4 mg/kg/twice monthly of eftansomatropin) discontinued due to pseudopapilloedema (optic disc drusen), which was assessed by the principal investigator to be mild with continuous frequency and possibly related to the study drug.

Injection site reactions (“ISRs”) were reported by 13 out of 40 subjects (32.5%) in the eftansomatropin cohorts. Pain was the most prominent and common symptom observed in 10 subjects. Also, six subjects reported redness, four reported itching, and one reported bruising, swelling and warmness. With respect to the Genotropin cohort, pain was the only ISR reported in 683 cases by 11 out of 14 subjects (78.5%). None of the ISRs led to discontinuation of treatment, and most of the reported ISRs posed no issue for the subjects and were resolved quickly. No safety signal was detected in laboratory parameters or vital signs for either eftansomatropin or Genotropin.

Pharmacokinetics. Half-life of eftansomatropin was 77.75–141.95 hours after a single dose and 43.92–55.66 hours (compared to 5.27 hours for Genotropin) after three months of multiple-dose administration.

Immunogenicity. Formation of treatment-emergent ADA with neutralizing property was reported in two subjects (one from Cohort 2 and one from Cohort 3) out of a total of 40 subjects randomized and dosed with eftansomatropin. With respect to the Genotropin cohort, the presence of treatment-emergent ADA with neutralizing property was not observed in any subject.

Clinical Efficacy. Subcutaneous administration of eftansomatropin over the dose range of 0.8 mg/kg/week–2.4 mg/kg/twice monthly resulted in an increase in aHV over the six-month study period. Subjects who received eftansomatropin at 0.8 mg/kg weekly, 1.2 mg/kg weekly, and 2.4 mg/kg twice monthly showed growth rates of 11.50, 11.54, and 11.86 cm/year, respectively, while the growth rate in the control group treated with Genotropin was approximately 11.24 cm/year.

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In an extension study in which all patients were put on eftansomatropin, greater than two-digit growth velocity remained until 12 months in all eftansomatropin cohorts, while the Genotropin cohort showed 9.14 cm/year at 12 months. Moreover, no remarkable slow-down of the growth velocity was observed in the second year in either patients who received eftansomatropin throughout, or in subjects who switched from Genotropin cohort.

Pharmacodynamics. The growth-promoting effect of eftansomatropin was accompanied by elevated serum IGF-1 levels. This hormone is an important biomarker, which mediates growth hormone’s biological effects. The Standard Deviation Score (“SDS”), which is a calculated score with reference to the normal age- and sex-matched IGF-1 levels, is a standardized parameter to compare IGF-1 levels across laboratories and populations. Mean IGF-1 SDS at the beginning of the study was below the lower limit of the normal range in all treatment arms. Following initiation of treatment, the IGF-1 SDS values quickly normalized by five days (Visit 2) and three weeks (Visit 3) after the initial treatment, respectively, for the eftansomatropin treatment arms and the Genotropin treatment arm. IGF-1 responses were maintained throughout the intended dosing interval, supporting both the weekly and twice monthly treatment regimens. IGF-1 mean peak levels were mostly within the upper limit of the physiologic range, which is considered safe in clinical practice.

Clinical Development Plan

In September 2020, the NMPA approved our IND application for a registrational Phase 3 trial of eftansomatropin in pediatric growth hormone deficiency (PGHD) in China. We expect to initiate this trial in the first quarter of 2021. This Phase 3 trial will be a multi-center, randomized, open-label, active-controlled clinical study designed to assess the safety, efficacy and pharmacokinetics of eftansomatropin in PGHD. The primary objective is to demonstrate non-inferiority of 1.2 mg/kg/week of eftansomatropin administered SC, compared to the active control Norditropin, a daily rhGH marketed in China. About 165 subjects will be enrolled and treated in the study.

Olamkicept (TJ301): A Potential Highly Differentiated IL-6 Blocker for Ulcerative Colitis and other Autoimmune Diseases

Summary

Olamkicept is the only clinical stage selective interleukin-6 (“IL-6”) inhibitor that works through the trans-signaling mechanism. IL-6 is an important cytokine driver in the propagation and maintenance of chronic inflammation in autoimmune diseases. Compared to the approved antibody drugs that directly block IL-6 or IL-6 receptor (“IL-6R”), olamkicept is expected to provide a novel alternative for the treatment of IL-6 mediated

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inflammation without affecting some of the normal physiological functions of IL-6, e.g., acute immune response against infection and metabolic regulation. Olamkicept demonstrated therapeutic effects in pre-clinical animal models of autoimmune diseases, including inflammatory colitis. Moreover, the safety and tolerability profile of olamkicept was studied in three clinical trials in Germany involving 128 subjects. We believe that olamkicept has the potential to become a highly differentiated therapy to target autoimmune diseases. We acquired an exclusive license from Ferring Pharmaceuticals to develop and commercialize olamkicept in Greater China and South Korea with an option of licensing worldwide rights. As part of our fast-to-market strategy for olamkicept, we selected ulcerative colitis (“UC”) as the first indication for the following reasons: (i) olamkicept was shown to be effective in animal models of colitis; (ii) an exploratory Phase 2a biomarker trial showed promising interim treatment effects of olamkicept in UC patients; and (iii) even though UC incidence is increasing rapidly, innovative biologic treatments for this disease are lacking in China. We are conducting an ongoing Phase 2 clinical trial in patients with active ulcerative colitis. The enrollment of this trial is complete with a total of 91 patients recruited. Topline data of this trial are expected to be released by early 2021. After clinical efficacy and differentiation are validated for UC, we plan to develop olamkicept in other inflammatory indications, in which IL-6 plays a role.

Therapeutic Options and Current Development

Our current therapeutic indication for development is UC. UC and Crohn’s disease (“CD”) are the main types of inflammatory bowel disease (“IBD”), which cause chronic and often relapsing inflammation of the large and small intestines, respectively. Anti-inflammatory drugs, such as 5-aminosalicylic acids (“5-ASAs”) and corticosteroids, are often used as initial treatment for UC. Immune system suppressors are also used to control inflammation in patients with UC, including azathioprine, mercaptopurine, and cyclosporine. Biologics that inhibit tumor necrosis factor alpha (TNF-α), including infliximab (Remicade), adalimumab (Humira), and golimumab (Simponi), are efficacious in some UC patients who fail to respond to conventional therapies. Entyvio, an integrin α4ß7 antibody that blocks lymphocytes from accumulating in the intestinal wall, was the first non-anti-TNF-α biologics approved for UC STELARA^® (ustekinumab), an anti-IL-12/IL-23 antibody was approved for the treatment of adult patients with moderately to severely active ulcerative colitis in June 2020. In China, Remicade and Entyvio are currently the only two biologics approved for treatment of UC.

There is a substantial unmet medical need in UC for a treatment agent(s) that is efficacious and safe through pathways beyond the traditional drug targets. The incidence of UC is increasing rapidly, but UC patients, especially those with a moderate-to-severe disease, have few treatment options, which have limited efficacy and considerable side-effects. For example, Jak1/3 kinase inhibitors can carry the risk of serious infections and malignancies. TNF-α inhibitors also have inherent side effects and do not work in all patients. Thus, as the only clinical stage selective interleukin-6 (“IL-6”) inhibitor that works through the trans-signaling mechanism, we believe olamkicept has the potential to become a highly differentiated IL-6 blocker for UC, if approved.

Advantages of Olamkicept

The existing IL-6 or IL-6R blockers cause total inhibition of IL-6 signaling and are associated with significant adverse events in the clinic, such as infection, gastrointestinal perforation, metabolic disturbances, and insulin resistance. Olamkicept is expected to provide a novel alternative as it works through a different mechanism, the trans-signaling pathway. This key advantage has been demonstrated in pre-clinical studies and three clinical trials conducted in Germany. The results indicated that olamkicept has no side effects on lipid, glucose or bone metabolism, and it has no agonistic activities that could activate receptors or trigger detrimental immune cascades. We expect that selective inhibition of IL-6 trans-signaling is an effective and safer approach to the treatment of chronic inflammation.

Mechanism of Action

Olamkicept is a homodimer of a fusion protein consisting of the extracellular domains of human glycoprotein130 (“gp130”) and the fragment crystallizable (Fc) domain of human IgG1. Mimicking the function

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of endogenous soluble gp130, olamkicept works as a decoy by binding to a complex consisting of IL-6 and soluble IL-6 receptor (“sIL-6R”), thereby preventing olamkicept from stimulating the trans-signaling pathway in cells that do not express IL-6R. The gp130 part selectively binds the IL-6/sIL-6R complex with high affinity (Kd=130 pM), whereas the Fc part initiates dimerization and offers longer half-life for the molecule. Olamkicept is not expected to affect the beneficial effects of IL-6, such as the acute immune response against infection mediated by the classical pathway.

Summary of Clinical Results

Ferring Pharmaceuticals has completed two Phase 1 trials to evaluate olamkicept’s preliminary safety and clinical pharmacology. Olamkicept was shown to be well-tolerated based on the clinical results collected from a total of 112 subjects exposed to the drug. In addition, a Phase 2a biomarker study in active IBD (known as the FUTURE study) has been completed in Germany with promising pharmacodynamic and clinical responses observed.

Phase 1 Clinical Trial: Single Dose Ascending Trial

Study Design. The first-in-human trial of olamkicept was a single dose, placebo-controlled, single-blind, randomized within dose, and parallel group dose-escalating trial. The trial recruited both healthy subjects and patients with Crohn’s Disease (“CD”) in clinical remission. The primary objective was to examine the safety, tolerability and pharmacokinetics after a single dose of olamkicept. Several dose levels were tested, ranging from 0.75 mg to 750 mg, with each dose level including six subjects receiving olamkicept and two receiving placebo.

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Pharmacokinetics. In healthy subjects and CD patients, olamkicept showed similar terminal half-life of 4.3 to 5.1 days. The maximum concentration (Cmax) in plasma and the area under curve (“AUC”) of the plasma drug concentration-time curve were dose proportional. For SC administration of olamkicept (60 mg), the Cmax was approximately 1.0 µg/mL at 2.3 days, and the bioavailability was approximately 48%.

Safety. Olamkicept was well-tolerated when administered as a single IV dose at up to 750 mg and as a single SC dose at 60 mg. No apparent dose-related AE was observed. Infusion was discontinued in two subjects due to mild to moderate infusion-related reactions, with skin symptoms such as urticaria and swelling, which were rapidly resolved.

Only one healthy subject in the 300 mg group showed non-neutralizing treatment-emergent ADAs at the follow-up visit five to six weeks after administration.

Phase 1 Clinical Trial: Multiple Dose Ascending Trial

Study Design. This trial was a placebo-controlled, double-blind, and randomized dose-escalating trial in healthy subjects. A total of 24 healthy subjects were randomized into three dose groups and received four weekly infusions of olamkicept at 75 mg, 300 mg or 600 mg.

Pharmacokinetics. PK characteristics were similar on the first and last treatment days of the multiple dose-ascending trial and were similar to results in the single dose-ascending study.

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Safety. There were only a few mild or moderate AEs reported across all treatment groups. One subject from the 600 mg group withdrew due to mild infusion-related reactions with urticaria and pruritus 30 minutes after administrating the first dose. No apparent dose-related trends or treatment-related change in vital signs, electrocardiogram or clinical chemistry parameters were observed. No ADAs were reported by any subject. Overall, olamkicept was well-tolerated when administered by IV at up to 600 mg once weekly for four weeks.

Overall Summary of Treatment-Emergent Adverse Events

Source: Ferring Pharmaceuticals

Note:

Phase 2a Biomarker Study in Active IBD (FUTURE Study)

Study Design. This was an open-label exploratory study to assess the mechanisms of molecular activity (effects on biomarkers), safety and tolerability of olamkicept in adult patients with active IBD. Nine UC patients and seven CD patients were dosed with olamkicept (600 mg, IV, q2w) for up to 12 weeks followed by 42 days of safety follow-up. Patients enrolled had moderately to severe active UC or ileocolonic CD with median disease duration of 5.3 (UC) and 6.9 (CD) years and with immunologically active inflammation (C-reactive protein >5 mg/l), who had failed conventional therapies and had no prior biologics treatment.

The primary endpoint was the proportion of patients with reduced mucosal expression of a predefined set of inflammation-relevant genes (TNFA, IL1A, REG1A, IL8, IL1B and LILRA) as a composite score. Objective assessments included centrally read endoscopies, histology readings, and various explorative molecular parameters and inflammatory biomarkers. The trial was sponsored and conducted by the University Hospital Schleswig Holstein and Paul-Ehrlich Institute (EUDRA-CT 2016-000205-36), with financial and material support from Ferring Pharmaceuticals. The study has been completed, and the abstract of the results was presented at the United European Gastroenterology Week meeting in October 2019.

Safety. Olamkicept was well-tolerated. Reported AEs were unspecific in nature and showed no signs of immune suppression. Five SAEs were observed, none of which were life-threatening or deemed to be related to olamkicept.

Pharmacokinetics. After single and repeated IV administration of olamkicept (600 mg, Q2W) to patients with UC and CD, similar serum exposure was observed after the first and last dosing events, with respect to Cmax and total exposure over 14 days. Maximal serum drug concentration after each dosing was reached at the end of infusion. The mean terminal half-life of olamkicept after the last administration was approximately 5.1 days. Circulating biological activity of olamkicept was confirmed by whole-blood STAT3 phosphorylation

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assays in all patients. A minimal and transient ADA production was observed in three patients. ADAs were only detected at week 12 and week 15, but no longer detectable at week 18.

Pharmacodynamics. In the assessment of the primary endpoint, it was observed that clinical remission was associated with a significant reduction of IL-1B, IL-8 and REG1A gene expression in the intestinal mucosa. Pathway analysis of blood transcriptome signatures showed an early molecular anti-inflammatory signature as early as four hours after treatment in all patients, irrespective of treatment outcome, which indicated a thorough inhibitory effect of IL-6 trans-signaling blockade on inflammatory pathways.

Clinical Efficacy. A preliminary clinical response was observed in both UC and CD patients, which appeared to be stronger in patients with UC than those with CD. Overall, 55% of UC patients (5/9) responded to olamkicept, with 22% (2/9) reaching clinical remission, whereas 29% of CD patients (2/7) responded to olamkicept, with 14% (1/7) reaching clinical remission. All three patients in clinical remission showed a fast and thorough induction of clinical, endoscopic, and immunologic remission within the first four weeks.

Clinical Development Plan

We are positioning olamkicept as a differentiated IL-6 blocker for a number of autoimmune diseases. The first target indication is active stage UC that is not well-controlled by conventional therapies such as mesalazine. We are conducting multi-regional Phase 2 clinical trial in Greater China and South Korea to assess the pharmacokinetics, safety, and efficacy of olamkicept in patients with active UC (NCT03235752). This is a randomized, double-blind, and placebo-controlled clinical trial with three treatment arms. The enrollment of this trial is complete with a total of 91 patients recruited. Topline data of this trial are expected to be released by early 2021.

Besides UC, we are evaluating the possibility of extending olamkicept to other autoimmune conditions where there is significant unmet medical need in China. We expect to initiate a second clinical trial for a chronic inflammatory disorder, such as systemic sclerosis or Castleman’s disease, in which IL-6 is implicated as a key pathogenic cytokine.

Enoblituzumab: The Most Advanced Clinical Stage Humanized B7-H3 Antibody as a Potential Immuno-oncology Treatment

Summary

Enoblituzumab is a humanized antibody directed at B7-H3, a member of the B7 family of T cell checkpoint regulators. B7-H3 is a promising immuno-oncology drug target as it is widely expressed across multiple tumor

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types and plays a key role in regulating immune response against cancers. Increasing pre-clinical and clinical evidence suggests that antibodies targeting the two T cell checkpoint molecules—B7-H3 and PD-1—work synergistically in treating cancer. Given B7-H3’s critical role, enoblituzumab has a wide range of cancer applications as either a monotherapy or in combination with PD-1 therapies. At the molecular level, enoblituzumab is engineered to possess an enhanced anti-tumor ADCC function and is at the forefront in global clinical development. Originally developed by MacroGenics, enoblituzumab has been evaluated in multiple clinical trials as a monotherapy or in combination with CTLA-4 or PD-1 therapies in patients with B7-H3-expressing cancers. Enoblituzumab is also being evaluated in a neoadjuvant Phase 2 study as a single agent in patients with intermediate and high-risk localized prostate cancer. The clinical studies so far have shown that enoblituzumab is well-tolerated, and it increased CD8 T cell infiltration in tumors with more focused T cell repertoires in patients treated with enoblituzumab as a monotherapy. Recent clinical studies conducted by MacroGenics indicate that combination therapy with enoblituzumab and pembrolizumab correlates with preliminary anti-tumor effects in recurrent or metastatic squamous cell carcinoma of the head and neck (“SCCHN”) and non-small cell lung cancer (“NSCLC”). We acquired the development and commercial rights of enoblituzumab from MacroGenics for Greater China. In the first quarter of 2021, MacroGenics expects to initiate a Phase 2 study of enoblituzumab in a chemo-free regimen in combination with either retifanlimab (an investigational PD-1 antibody) in front-line patients with SCCHN who are PD-L1 positive or with tebotelimab (an investigational PD-1 x LAG-3 bispecific DART^® antibody) in SCCHN patients who are PD-L1 negative. We expect to participate in a subsequent Phase 3 global study if and when initiated, as we deem appropriate. In addition, considering the dynamic regulatory environment and evolving clinical practice, we have been continually refining the development of enoblituzumab in our territory. As more clinical and pre-clinical data become available, further clinical trials may be planned together with MacroGenics to extend enoblituzumab to other cancer indications in China and/or globally.

Therapeutic Options and Current Development

Our initial therapeutic indication is head and neck cancer. Head and neck cancers occur in various parts of the head and neck, including the mouth, nose, throat and salivary glands. More than 90% of head and neck cancers are classified as SCCHN, which begin in the squamous cells that line the moist, mucosal surfaces inside the head and neck. The treatment principles and regimens for head and neck cancer in China are similar to those in the rest of the world. Treatment strategies often depend on the location and stage of the cancer, the patient’s physical status, and response to prior treatments. Early-stage disease is primarily treated with surgical resection, while patients with locally advanced, recurrent or metastatic disease are typically treated with drug therapy. The combination of surgery and drug therapy, with or without radiation therapy, is the current standard of care for Stage 3 SCCHN patients with locally advanced disease. Platinum-based chemotherapy regimens are widely used as first-line therapies for Stage 4 and distant relapse patients. Erbitux (cetuximab from Eli Lilly and Merck KGaA) was approved in 2006 as a first-line treatment of locally advanced SCCHN in combination with radiation therapy. Regimens containing Erbitux, platinum-based chemotherapy, and 5-fluorouracil, known as EXTREME, are often considered as the standard of care for first-line treatment of distant relapse SCCHN. However, only about 35% of patients respond to EXTREME, and the resulting overall median survival is only 10.1 months. Furthermore, about half of the patients on first-line therapies need later-line therapies.

In addition, even second-line therapy is highly varied, including single-agent docetaxel or paclitaxel, Erbitux monotherapy, and Erbitux and paclitaxel combination therapy. In 2016, PD-1 inhibitors were approved globally as second-line therapies. In 2019, Keytruda (pembrolizumab from Merck & Co), used as a single agent or in combination with chemotherapy, was approved by the FDA as first-line therapy for patients with metastatic or unresectable recurrent SCCHN. The average ORR for second-line therapies has been less than 15%.

As such, we believe that SCCHN patients, especially those with late stage or relapsed disease, need more efficacious treatments with fewer side effects, which represents a significant unmet medical need for immunotherapy and targeted therapy.

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Advantages of Enoblituzumab

Enoblituzumab is the most advanced clinical stage humanized B7-H3 antibody as a potential immuno-oncology treatment. The foregoing statement applies only to conventional therapeutic B7-H3 antibodies and does not include radio-labeled B7-H3 antibodies in development by Y-mabs Therapeutics. Targeting B7-H3 offers several advantages over other target options within the class of T cell checkpoint molecules. First, B7-H3 is a tumor-associated antigen that is over-expressed in a variety of solid tumors while its expression in normal tissues is rather limited, enabling the tumor killing mechanism of enoblituzumab. Second, B7-H3 is a unique checkpoint whose expression in tumors is associated with disease prognosis. For example, biomarker analysis of more than 400 NSCLC patients revealed that among all the elevated immune checkpoint inhibitors, including PD-1/PD-L1, PD-L2, B7-H3, TIM-3, BTLA and CTLA4, only B7-H3 is negatively correlated with clinical efficacies of neoadjuvant treatments (Lou et al., Clinical Cancer Research, 2016). Furthermore, recent studies have shown that when combined with a PD-1 antibody, a blockade of B7-H3 results in superior treatment effects in relevant cancer animal models while another study indicates that B7-H3 expression correlates with a lack of anti-PD-1 response (Yonesaka et al., Clinical Cancer Research, 2018). The advantages summarized above make B7-H3 a favorable tumor target for immuno-therapeutic intervention.

Mechanism of Action

Enoblituzumab (MGA271) is an investigational humanized immunoglobulin (IgG1/kappa monoclonal antibody) that binds to B7 homolog 3 (B7-H3). This antibody consists of an engineered human IgG1 fragment crystallizable (Fc) domain that imparts increased affinity for the human activating Fc gamma receptor FcgRIIIA (CD16A) and decreased affinity for the human inhibitory FcgRIIB (CD32B). The engineered Fc domain confers enoblituzumab with enhanced target-specific antibody-dependent cellular cytotoxicity (“ADCC”) in vitro and anti-tumor activity in preclinical studies. Therefore, enhanced cytolysis of B7-H3-expressing tumor cells is a mechanism that supports the development of this molecule as an antineoplastic agent.

In addition, data suggest that enoblituzumab impacts T-cell homeostasis in vivo. Cancer patients display a more narrowly focused T-cell repertoire following enoblituzumab treatment compared to their baseline repertoire distribution. Moreover, enhanced local T-cell infiltration has been observed in prostate cancer patients treated with enoblituzumab.

These data are consistent with the notion that enoblituzumab is capable of engaging both innate and adaptive immunity as mediators of its anti-tumor activity.

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Summary of Clinical Results

Phase 1 Study of Enoblituzumab Monotherapy

Study Design. This was an open-label, multi-dose, single-arm, multi-center, and dose-escalation study to define safety, tolerability, maximum tolerated dose (“MTD”), PK, immunogenicity, and potential anti-tumor activity of enoblituzumab in patients with refractory cancers that express B7-H3 conducted by MacroGenics. In the dose escalation segment of the study, six doses (0.15–15 mg/kg QW) were evaluated in a conventional “3+3” design.

No MTD or dose-limiting toxicity (“DLT”) was observed in the dose escalation phase, so the highest administered dose, 15 mg/kg, was used in the cohort expansion, in which patients received weekly infusions of enoblituzumab in eight-week cycles for up to 12 cycles. Tumor evaluation was carried out by both Response Evaluation Criteria in Solid Tumors (“RECIST”) and immune-related response criteria (“irRC”) with an initial response assessment after eight weeks. This entailed seven tumor-specific cohorts, including melanoma (post-checkpoint inhibitor failure, n=31), head and neck cancer (n=19), prostate cancer (n=34), triple-negative breast cancer (n=17), renal cell carcinoma (n=16), NSCLC (n=8), and bladder cancer (n=12).

Safety. Interim data analysis as of the data cut-off date of April 13, 2017, indicates that enoblituzumab is well-tolerated. Treatment-related AEs (per investigator assessment) were experienced by 134 out of 170 (78.8%) patients, most of which were infusion-related reactions (n=62, 36.5%), fatigue (n=54, 31.8%), nausea (n=32, 18.8%), and chills (n=24, 14.1%). Only three out of 179 patients (1.7%) had a treatment-related discontinuation, and 13 (7.3%) patients experienced treatment-related Grade 3 or higher AEs (fatigue, infusion-related reactions, and nausea), assessed based on Common Terminology Criteria for Adverse Events (CTCAE) criteria version 4.0. Mild to moderate infusion-related reactions were managed with low dose steroids or a decrease of the infusion rate. No severe immune-mediated toxicity was observed.

Pharmacokinetics. Preliminary analysis and population PK modeling based on 18 patients dosed at 15 mg/kg indicate that PK of enoblituzumab was characterized primarily by target-mediated drug disposition and was consistent with a typical human IgG1 with near-linear PK.

Efficacy. Evidence of decreased size of target and non-target lesions as well as extended time to progression were observed across a broad range of tumors, including heavily pretreated cancers. Three patients achieved PR (partial responses) by RECIST out of a total of approximately 71 patients being evaluated.

Phase 1 Study of Enoblituzumab in Combination with Pembrolizumab

Study Design. This is an open-label, dose escalation, cohort expansion, and efficacy follow-up study of enoblituzumab in combination with pembrolizumab conducted by MacroGenics. The dose escalation phase is designed to characterize the safety and tolerability of the combination and to define the maximum tolerated or maximum administered dose. Three dose levels of enoblituzumab (3, 10, 15 mg/kg, IV, QW) have been evaluated in combination with pembrolizumab (2 mg/kg, IV, Q3W). No MTD has been identified, and so the maximum administered dose of enoblituzumab (15 mg/kg) in combination with pembrolizumab was given to additional cohorts of patients enrolled during the cohort expansion phase. The efficacy follow-up period consists of the two-year period after administering the final dose of the study drug. All tumor evaluations are carried out by both RECIST and irRC.

A total of 133 patients with B7-H3-expressing melanoma, squamous cell carcinoma of the head and neck (SCCHN), non-small cell lung cancer (“NSCLC”), and urothelial cancer have been treated in the study. The

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interim results as of the data cut-off date, October 12, 2018, were presented at the 2018 Annual Meeting of the Society for Immunotherapy of Cancer (SITC), which showed an ORR (overall response rate) that compared favorably with historical experience with anti-PD-1 monotherapy in anti-PD-1/PD-L1 naive patients.

Safety. The combination of enoblituzumab and pembrolizumab demonstrated acceptable tolerability in patients treated to date. Grade 3 or higher AEs, assessed based on Common Terminology Criteria for Adverse Events (CTCAE) criteria version 4.0, occurred in 27.1% of all patients. Drug-related AEs of all grades included infusion-related reactions (n=73, 54.9%), fatigue (n=37, 27.8%), rash (n=14, 10.5%), and nausea (n=12, 9.0%). The incidence of immune-related AEs in the study was comparable to that observed in patients who received anti PD-1 monotherapy. Nine patients experienced drug-related AEs leading to treatment discontinuation. Drug-related AEs and immune-related AEs of special interest are summarized in the table below.

Drug-Related and Immune-Related Adverse Events

During Combination Treatment with Enoblituzumab and Pembrolizumab

Source: MacroGenics.

Clinical Efficacy. As of October 12, 2018, the cut-off date of the most recent data analysis, preliminary results indicated that among the 18 response-evaluable SCCHN patients who had not previously received

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PD-1/PD-L1 therapies, six patients (33.3%) had confirmed partial responses (“PRs”). Among the subset of patients with 10% or higher B7-H3 tumor expression, six out of 15 (40.0%) had confirmed PRs (see figure below) compared to previously reported SCCHN patients treated with PD-1 monotherapy, which achieved ORRs ranging from 13% to 16%.

Anti-tumor Activity in Anti-PD-1/PD-L1-Naive SCCHN Patients

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Among 14 response-evaluable NSCLC patients who had not previously received PD-1/PD-L1 therapies and were PD-L1 negative, i.e., PD-L1 less or equal to 1%, five patients (35.7%) had confirmed PRs (see figure below). Objective response rates ranging from 8% to 17% were reported in PD-L1 negative NSCLC patients treated with PD-1 monotherapy.

Anti-tumor Activity in PD-1-Naive NSCLC Patients Who are PD-L1 Negative (PD-L1 < 1%)

Tumor Volume Change from Baseline (%)

In the two figures above, CR (complete response) means the disappearance of all target lesions, with the reduction of all pathological lymph nodes to <10 mm; PR (partial response) means at least a 30% decrease in the sum of the target lesions, in comparison to the baseline sum diameter; PD (progressive disease) means a 20% increase in the sum of the diameters in comparison to the smallest sum of diameters with an absolute increase of at least 5 mm, provided that any new lesion is considered progressive disease; and SD (stable disease) means meeting neither the criteria for partial response nor for progressive disease, in comparison to the smallest sum of diameters.

Clinical Development Plan

We acquired the development and commercial rights of enoblituzumab from MacroGenics for Greater China. In the first quarter of 2021, MacroGenics expects to initiate a Phase 2 study of enoblituzumab in a chemo-free regimen in combination with either retifanlimab (an investigational PD-1 antibody) in front-line patients with SCCHN who are PD-L1 positive or with tebotelimab (an investigational PD-1 x LAG-3 bispecific DART^® antibody) in SCCHN patients who are PD-L1 negative. We expect to participate in a subsequent Phase 3 global study if and when initiated, as we deem appropriate. In addition, considering the dynamic regulatory environment and evolving clinical practice, we have been continually refining the development of enoblituzumab in our territory.

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Global Portfolio

Plonmarlimab (TJM2): A GM-CSF Monoclonal Antibody for Rheumatoid Arthritis and CAR-T-related Therapies

Summary

Plonmarlimab is an internally discovered neutralizing antibody against human granulocyte-macrophage colony-stimulating factor (“GM-CSF”), an important cytokine that plays a critical role in chronic inflammation and destruction in autoimmune diseases such as rheumatoid arthritis (“RA”). Plonmarlimab is a humanized IgG1 that displays high affinity binding to GM-CSF and blocks its signaling and downstream effects. Plonmarlimab is being developed for the treatment of autoimmune and inflammatory diseases, including RA and cytokine release syndrome (“CRS”). We have completed a single-dose first-in-human study in healthy volunteers in the United States. In China, plonmarlimab is the first antibody of its class entering clinical development. We dosed the first patient in a Phase 1b study of plonmarlimab in August 2020 in China. We may expand plonmarlimab to other autoimmune and inflammatory indications with high unmet medical need, where GM-CSF is known as a pathogenic cytokine in disease activity and progression. If approved, plonmarlimab is expected to provide an effective treatment option as a disease-modifying anti-rheumatic drug (“DMARD”) therapy.

In addition, since the COVID-19 outbreak, we have sprung into action to prioritize plonmarlimab in response to the urgent medical needs. In May 2020, we announced preliminary results from part 1 of a clinical study in the United States of plonmarlimab in patients with cytokine release syndrome (CRS) associated with severe COVID-19, in which plonmarlimab was found to be well tolerated. We are currently conducting part 2 of this clinical trial to evaluate the efficacy, safety and cytokine levels following a single dose of 6 mg/kg plonmarlimab or placebo (standard care) in patients with severe COVID-19. We are currently in discussion with the FDA to finalize the plan for plonmarlimab in relation to clinical development and potential registration in the United States.

Therapeutic Options and Current Development

Our current therapeutic indication is RA, a systemic chronic inflammatory disease considered to be one of the most prevalent immune-mediated inflammatory diseases. RA is nearly always polyarticular and causes joint destruction, deformity, and loss of function. Extra-articular manifestations include cardiopulmonary diseases, eye diseases, Sjogren’s syndrome, rheumatoid vasculitis and neurological diseases. Current therapies for RA in China include traditional Chinese medicine, corticosteroids, and DMARDs, including immunosuppressants and targeted therapies such as TNF inhibitors. Although the market for RA has become more competitive in China, new medicines targeting different pathways with greater clinical efficacy and safety remain a significant unmet need. Our GM-CSF antibody targets an entirely different disease pathway and has these desired characteristics to treat RA.

Clinical evidence supporting the role of a GM-CSF antibody in RA is highlighted in a few recent global studies. For example, both otilimab (MOR103), a GM-CSF antibody from MorphoSys and GSK, and mavrilimumab, a GM-CSF receptor antibody from Medimmune, have shown an early onset of clinical responses in Phase 2 proof-of-concept trials with RA patients. In addition to RA, attempts to develop a GM-CSF antibody for treating other autoimmune diseases, such as ankylosing spondylitis, are being studied by Amgen and Takeda. These autoimmune conditions involve the same autoimmune cell types, including macrophages, and neutrophils and the same connective tissues such as bones, joints, and tendons. Given the large patient population affected and the burden of these diseases, we are keen to explore the therapeutic role of plonmarlimab in treating these diseases, if initial studies in RA patients meet primary end-points.

The therapeutic role of plonmarlimab goes beyond autoimmune diseases. A recent study indicates that GM-CSF plays a critical role in serious side effects associated with chimeric antigen receptor (CAR)-T therapy,

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such as cytokine release syndrome (“CRS”) and neurotoxicity. As CAR-T therapy has become an effective treatment option for certain cancer types, finding a treatment solution for CAR-T-related toxicities that occur frequently and can turn into a serious and potentially fatal condition becomes an urgent need. These severe toxicities add to the morbidity and mortality of CAR-T therapy. CRS is caused by a massive release of circulating cytokines by expanding CAR-T cells, and GM-CSF is one of the key cytokines of CRS. Currently, there are no effective therapies to prevent CRS or neurotoxicity. Tocilizumab, an IL-6 receptor antagonist, is approved for severe CRS with limited therapeutic coverage. Recent studies indicate that neutralizing GM-CSF in vivo may ameliorate and potentially prevent CRS and neuroinflammation without affecting CAR-T cell activity. Humanigen has teamed up with Kite to evaluate lenzilumab, a GM-CSF antibody, as a preventive or treatment agent in association with Yescarta, an approved CD19-directed CAR-T therapy. In parallel with an RA clinical trial, we are seeking opportunities to co-develop plonmarlimab as a treatment option for CRS associated with CAR-T therapy.

Furthermore, emerging data indicate that the common features among COVID-19 patients particularly those severely or critically ill include lymphopenia and significantly elevated serum levels of pro-inflammatory cytokines including GM-CSF and IL-6, IFN-gamma. Moreover, recently published data indicate that COVID-19 can induce a cytokine storm instigated by extensive immune cell infiltration and the release of GM-CSF and IL-6. These inflammatory cytokines drive aberrant activation of monocytes and lymphocytes which in turn provoke increased production of more cytokines and chemokines in a feed forward cycle, resulting in the cytokine storm, or CRS, severe pulmonary complications and mortality. Therefore, blocking of GM-CSF by plonmarlimab may impact the upstream of cytokine storm network to prevent or curb the hyperinflammation and immunopathology which may be responsible for the complications associated with severe COVID-19.

Advantages of Plonmarlimab

Based on reported clinical findings with front-runner GM-CSF antibodies compared to other RA biologics that are clinically used, we have the following expectations:

Mechanism of Action

GM-CSF is a central driver cytokine in orchestrating an innate immune response during inflammation. It is responsible for myeloid cell proliferation and functions, such as chemotaxis, adhesion, phagocytosis, and microbial killing. Importantly, GM-CSF can polarize macrophages into a pro-inflammatory M1 phenotype and is known to induce an inflammatory cascade involving other pro-inflammatory cytokines such as TNF, IL-1, IL-6, IL-12, and IL-23. It is evident that GM-CSF plays a crucial role in the pathogenesis and disease progression of multiple autoimmune conditions. The action of GM-CSF is mediated by binding of its cognate receptor on target cells and subsequent phosphorylation of signal transducer and activator of transcription 5 (“STAT5”).

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Plonmarlimab specifically binds to human GM-CSF with high affinity and can block GM-CSF from binding to its receptor, thereby preventing downstream signaling and target cell activation. As a result, it can effectively inhibit inflammatory responses mediated by macrophages, neutrophils, and dendritic cells, leading to reduced tissue inflammation and damage.

Summary of Pre-clinical Results

A series of nonclinical studies have been conducted to evaluate the pharmacology, PK, and toxicology profiles of plonmarlimab. Plonmarlimab could potently bind to human and monkey GM-CSF but not rodent GM-CSF. Plonmarlimab neutralized GM-CSF in a number of pharmacological studies in vitro and in vivo. Plonmarlimab demonstrated linear PK behavior in single dose IV and SC studies in monkeys with a half-life characteristic of IgG and a low ADA potential. Weekly plonmarlimab treatment significantly reduced arthritis score and clinical symptoms in monkeys with established collagen-induced arthritis (a model of RA). Both 4-week and 13-week repeat-dose GLP general toxicology studies in non-human primates have been completed with sufficient safety margin. The nonclinical studies performed to date continue to support plonmarlimab in clinical studies.

Summary of Clinical Results

Completed single-dose first-in-human study in healthy volunteers in the United States

Based on the pre-clinical results, we initiated a first-in-human study in healthy volunteers in the United States (NCT03794180). This study has now been completed with a clinical study report (CSR) available.

Study design. This randomized, double-blind, placebo-controlled, and single dose-ascending study was designed to assess the safety, tolerability, PK/PD, and immunogenicity of plonmarlimab (referred to as TJ003234) in healthy volunteers. We have enrolled and completed dosing of four planned cohorts at 0.3, 1, 3 and 10 mg/kg dose levels, with each cohort consisting of eight subjects randomized into six receiving plonmarlimab and two receiving placebo IV infusions.

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Safety. Plonmarlimab was well tolerated following a single IV dose up to 10 mg/kg in healthy subjects with no MTD reached. There were no interruptions in dosing or early withdrawals. Fourteen males and 18 females participated in the study. The majority of AEs were mild to moderate in nature. No serious adverse events were reported during the study. Overall, 8 of the 24 subjects who received plonmarlimab and 3 of the 8 subjects on placebo reported treatment-related treatment-emergent adverse events (TEAEs). The most common AEs experienced by subjects dosed with plonmarlimab were headache (25%) and protein urine (25%). These AEs were also the most common AEs reported by subjects receiving placebo (37.5% and 37.5%, respectively).

Pharmacokinetics. Serum concentrations of plonmarlimab (TJ003234) were determined by anti-idiotypic antibody capture immunoassay and PK parameters were analyzed by noncompartmental analysis. Results showed that over the dose range of 0.3 mg/kg to 10 mg/kg, both C_max and exposure increased in an approximately dose-proportional manner, with C_max increased from 5.75 µg/mL to 260 µg/mL and AUC₀-last increased from 90.5 day*µg/mL to 3780 day*µg/mL (see Figure below). In addition, t_1/2 was approximately 3 weeks across the tested dose range. Clearance of plonmarlimab decreased with increasing dose. Volume of distribution decreased slightly with increasing dose. In terms of immunogenicity, two subjects in the 3 mg/kg plonmarlimab cohort and 1 placebo subject were positive for ADA. No subject in the 10 mg/kg dose level was positive for ADA.

Pharmacodynamics. Four hours after dosing, the induction of STAT5 phosphorylation by ex vivo GM-CSF in circulating monocytes was inhibited by at least 70% compared to the placebo following a single dose of plonmarlimab for all dose groups. Plonmarlimab inhibited GM-CSF-stimulated STAT5 phosphorylation levels by more than 90% in subjects in the 3 mg/kg and 10 mg/kg cohorts at 4 h to up to 2 weeks after dosing, suggesting the saturation of STAT5 inhibition by the treatment at doses of 3 mg/kg and above.

Ongoing study for plonmarlimab to treat COVID-19 patients with cytokine release syndrome

We are conducting a study of plonmarlimab in the United States in patients with CRS associated with severe COVID-19. This study adopts a robust clinical trial design and represents one of the first double-blind, placebo-controlled and randomized studies to evaluate the therapeutic role of anti-GM-CSF antibody in severe COVID-19 patients.

Part 1 of the study evaluated the safety and tolerability of plonmarlimab in a total of 24 patients who were randomized at a ratio of 1:1:1 to receive either a single dose of 3 mg/kg plonmarlimab, a single dose of 6 mg/kg

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plonmarlimab or placebo (standard care), administered by intravenous (IV) infusion. Data from part 1 of the study were reviewed by a data monitoring committee (DMC) to assess patient safety and overall conduct of the study. After comprehensive review and analysis, the DMC concluded that we could commence part 2 of the study as planned, indicating that plonmarlimab was safe and well-tolerated in severe COVID-19 patients in the study. The DMC also endorsed recommended protocol changes, including broadening the inclusion criteria and dosing all patients at 6 mg/kg of plonmarlimab or placebo. Part 2 of the study with a design similar to part 1 will target the same patient population and is enrolling patients. It will evaluate the efficacy, safety and cytokine levels following a single dose of 6mg/kg plonmarlimab or placebo in patients with severe COVID-19. To preserve the original clinical trial design with blinding and data integrity, the clinical efficacy data will be revealed upon completing part 2 of this study.

DMC’s assessment and positive recommendation is a testament to our science-focused clinical development capabilities. We believe we have the most advanced anti-GM-CSF study in COVID-19 that could potentially lead to registration of plonmarlimab in the United States. The DMC’s confirmation of plonmarlimab’s safety profile bolsters the drug’s potential to address the complications among the severe and critically ill and could ultimately save lives.

Clinical Development Plan

Data from this first-in-human study support continued development of plonmarlimab. In August 2020, we announced that the first patient has been dosed in a Phase 1b study to evaluate plonmarlimab in patients with RA in China. This trial is a multi-center, double-blind, placebo-controlled study of about 63 patients who will receive a single dose or multiple doses of the treatment for up to eight weeks.

In addition, we are developing plonmarlimab to treat cytokine storm in severe and critically ill patients caused by COVID-19. We are currently conducting part 2 of the clinical trial in the United States to evaluate the efficacy, safety and cytokine levels following a single dose of 6 mg/kg plonmarlimab or placebo (standard care) in patients with severe COVID-19. We are currently in discussion with the FDA to finalize the plan for plonmarlimab in relation to clinical development and potential registration in the United States. The results from these planned COVID-19 studies will also be used to further evaluate the potential therapeutic role of plonmarlimab in reducing or preventing cytokine storm and neurotoxicity associated with CAR-T therapy through collaborations.

Lemzoparlimab (TJC4): A Potential Highly Differentiated CD47 Antibody for Immuno-Oncology

Summary

Lemzoparlimab is a fully human CD47 monoclonal antibody that we have discovered and developed internally for cancer immunotherapy. CD47 has emerged as one of the most promising immuno-oncology targets. Unlike other immuno-oncology targets being explored, the CD47-SIRPα pathway is involved in tumor progression by delivering a “don’t eat me” signal to tumor-engulfing macrophages, thereby protecting tumors from natural attacks by macrophages. Blockade of this pathway by CD47 antibody represents one of the most effective tumor killing mechanisms. However, due to the inherent epitope sharing between tumor cells and normal red blood cells (“RBCs”), the first-wave of clinical stage CD47 antibodies were found in clinical trials to bind to RBCs and cause significant hematologic adverse effects, such as severe anemia, which has hampered the development of these CD47 antibodies as a potential cancer therapy.

We developed lemzoparlimab by design to possess a unique property or differentiation, to minimize binding to RBCs while retaining anti-tumor activities in line with other antibodies of the same class. This key differentiation is achieved through additional RBC counter-screening to select rare antibody clones that bind to CD47 with high affinity but do not bind to or bind minimally to RBCs. Lemzoparlimab has been validated in a series of in vitro and in vivo pre-clinical studies, which have consistently shown a unique RBC-sparing profile

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comprised of minimal RBC binding, lack of hemagglutination and no significant adverse hematologic changes in cynomolgus monkeys even when used at a high dose (100 mg/kg). In addition, the topline results of the completed Phase 1a dose escalation monotherapy trial in the United States have demonstrated the differentiated profile of lemzoparlimab in drug safety and favorable pharmacokinetics in cancer patients. The key findings include: (i) lemzoparlimab was well tolerated up to 30 mg/kg on a weekly basis without priming dosing strategy, and no dose-limiting toxicity and no clinical or laboratory evidence of hemolytic anemia were observed throughout; (ii) lemzoparlimab PK appears to be linear at mid to high dose levels following a single dose with no significant “sink effect” and (iii) one confirmed Partial Response (PR) was observed in the 30 mg/kg cohort (N=3), and this patient had failed prior treatments with checkpoint inhibitors. Three patients achieved Stable Disease (SD). Therefore, we believe that lemzoparlimab, if approved, will be a potentially highly differentiated anti-tumor CD47 antibody with the advantage of minimizing hematologic side effects.

In September 2020, we received the NMPA approval for a Phase 1 clinical trial of lemzoparlimab in relapsed or refractory advanced lymphoma in China as part of the ongoing international multi-center trial. In addition, lemzoparlimab is being evaluated in a Phase 1/2a clinical trial in China in patients with relapsed or refractory acute myeloid leukemia (r/r AML) or myelodysplastic syndrome (MDS), and we anticipate reporting top-line results in early 2021. We have also entered into a clinical trial collaboration and supply agreement with Merck Sharp & Dohme Corp, or MSD, through a subsidiary, under which we will sponsor a Phase 1 clinical trial in the United States evaluating lemzoparlimab in combination with KEYTRUDA^® (pembrolizumab), MSD’s anti-PD-1 therapy, in patients with multiple types of solid tumors. In September 2020, we granted AbbVie a global license, excluding Mainland China, Hong Kong and Macau, to develop and commercialize lemzoparlimab (as well as certain other compounds directed against CD47), and we will retain all rights to develop and commercialize lemzoparlimab in Mainland China, Hong Kong and Macau.

Therapeutic Options and Current Development

We plan to evaluate the therapeutic role of lemzoparlimab in a variety of solid tumors, such as cancers of the ovary, lung, liver, pancreas, breast and colon, and hematological malignancies such as AML/MDS, lymphoblastic leukemia, and NHL. Although PD-1/PD-L1 therapies represent a new paradigm in cancer treatment, less than 40% of cancer patients have a clinically meaningful response to PD-1/PD-L1 treatment. As a result, targeting other immune components or cells involved in the immune system’s anti-tumor mechanism has become an area of active pursuit in the field of immuno-oncology. Lemzoparlimab is one such innovative and promising therapeutic antibody, which is capable of mobilizing macrophage functions for effective and direct tumor-killing. Currently, a number of CD47 antibodies are in clinical development by biotech companies including Gilead/Forty-Seven, Inc., Surface Oncology and Arch Oncology. The most advanced asset, magrolimab, orginally developed by from Forty-Seven, Inc., is in Phase 3 clinical studies for multiple cancer indications. However, almost all clinical trials with CD47 antibodies so far have shown significant hematologic adverse effects, likely due to inherent RBC-binding properties of generic CD47 antibodies, and as a result, some clinical studies had to be either terminated or managed with extra cautions.

Advantages of Lemzoparlimab

Lemzoparlimab has similar sub-nanomolar binding affinity as other CD47 antibodies and exhibits comparable anti-tumor activity. The key advantage of lemzoparlimab is its minimal binding to RBCs, thus potentially avoiding or minimizing inherent hematologic adverse effects typically seen in other CD47 antibodies in clinical trials. This differentiated property of lemzoparlimab is, at least in part, due to its unique epitope interaction as revealed by crystallography, which is different from those recognized by other CD47 antibodies currently in clinical development based on publicly available information. The differentiation of lemzoparlimab is highlighted in a series of pre-clinical studies summarized as the following: (i) lemzoparlimab displays only minimal RBC-binding even at high antibody concentrations by flow cytometry; (ii) lemzoparlimab does not induce RBC agglutination even in a high concentration range; and (iii) most importantly, lemzoparlimab does not cause significant hematologic changes or systemic toxicologic effects even at high doses in multiple cynomolgus

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monkey studies, including a pivotal 4-week GLP toxicity study. Taken together, lemzoparlimab has a potentially better clinical safety profile and may be used in a broader patient population to explore its anti-tumor potential compared to other clinical stage competitor molecules.

Mechanism of Action

Lemzoparlimab blocks the interaction between CD47 expressed on cancer cells and SIRPα expressed on macrophages, leading to increased phagocytosis of cancer cells by macrophages. Blockade of CD47 by lemzoparlimab may also promote the development of anti-tumor T cell responses, resulting from increased tumor antigen presentation by professional antigen-presenting cells such as macrophages and dendritic cells. In addition to stimulating the phagocytosis of cancer cells, CD47 blockade was shown to involve other anti-tumor mechanisms, such as the enhancement of ADCC, direct induction of apoptosis (programmed cell death) of cancer cells, induction of differentiation of cancer stem cells, and inhibition of metastasis.

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Summary of Clinical Results

The ongoing phase 1 study of lemzoparlimab in the US is an open-label, multi-center, multiple dose study conducted in two parts to determine safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD) and efficacy of lemzoparlimab administered alone and in combination (NCT03934814). The first part is comprised of a single agent dose escalation followed by two separate combination regimens in an escalating dose range (Part 1b with pembrolizumab; Part 1c with rituximab). The second part is a dose expansion study in the combination therapies.

The monotherapy dose escalation (Part 1a) has been completed and the initial data from the monotherapy were presented at Society for Immunotherapy of Cancer (SITC) in November 2020. Lemzoparlimab was well tolerated up to 30 mg/kg on a weekly infusion schedule without priming dosing strategy. No dose-limiting toxicity and no clinical or laboratory evidence of hemolytic anemia were observed throughout. Maximal tolerable dose (MTD) was not reached. Lemzoparlimab PK appeared to be linear at mid to high dose levels following a single dose with no significant “sink effect”. One confirmed Partial Response (PR) was observed in the 30 mg/kg cohort (n=3). This patient had failed prior treatments with checkpoint inhibitors. Three patients achieved Stable Disease (SD). Recruitment of patients for the dose escalation study of lemzoparlimab in combination with pembrolizumab or rituximab is ongoing.

Part 1a of Phase 1 Clinical Trial: Single Agent Dose Escalation First-in-patient Trial

Study Design. NCT03934814 is an open label, Phase 1 study to evaluate the safety, tolerability, maximal tolerable dose (MTD) or maximum administered dose (MAD), PK, PD, and recommended phase 2 dose (RP2D) of lemzoparlimab in subjects with advanced relapsed or refractory solid tumors and lymphoma. Part 1 of the study comprises a single agent dose escalation in a standard 3+3 design (1a) and 2 separate dose escalations in combination with pembrolizumab (1b) or rituximab (1c). Part 2 is a dose expansion study. Lemzoparlimab was administered as weekly IV infusions in successive dose cohorts (1, 3, 10, 20 and 30 mg/kg) without any priming dose. Twenty patients were enrolled. Clinical data from the Part 1a study were reported as of November 2020.

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Safety. No dose limited toxicities (DLTs) or drug-related severe adverse event (SAE) were reported throughout the study. All treatment-related adverse events (TRAEs) were either Grade 1 or Grade 2 except one Grade 3 lipase increase was reported.

A transient reduction in the hemoglobin levels during the first cycle was observed across all cohorts. The average drop was ~10% and was not dose dependent. This finding is consistent with the results of pre-clinical GLP toxicity studies. None of the drug-related anemia reported was considered to be severe or hemolytic in nature.

Pharmacokinetics. The PK profile of lemzoparlimab appeared linear at doses higher than 10 mg/kg following a single dose administration, while its exposure was greater than dose proportional over the dose range of 1 to 10 mg/kg, suggesting that at higher doses, lemzoparlimab could overcome the CD47 “sink effect”. Five subjects were confirmed positive for anti-drug antibodies (ADA) following the first treatment: 3 were from 1 mg/kg, 1 from 3 mg/kg and 1 from 10 mg/kg. No impact of ADA was seen on safety or PK profiles.

Pharmacodynamics. Maximal saturation of CD47 receptor occupancy (RO) on peripheral T cells was achieved at 20 and 30 mg/kg following weekly administration of lemzoparlimab.

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Preliminary Efficacy. One confirmed Partial Response (PR) was observed in the 30 mg/kg monotherapy cohort (1/3) with 6 cycles completed so far. The patient who had metastatic melanoma had failed prior systemic treatment of nivolumab and ipilimumab.

Summary of Pre-clinical Results

CD47-related In Vitro and In Vivo Anti-tumor Activities

Lemzoparlimab exhibits high-affinity binding to human CD47 protein and CD47-expressing tumor cells at the nanomolar level and effectively blocks interaction of CD47 with its receptor SIRPα. As compared with other CD47 antibodies currently under clinical development, lemzoparlimab (TJC4) demonstrated comparable potency in the enhanced macrophage-mediated phagocytosis of Raji tumor cells (see Figure A below) and comparable anti-tumor activity in the HL-60 leukemia and Raji xenograft models (see Figure B below). Moreover, when combined with rituximab, lemzoparlimab exhibited a markedly enhanced inhibition on tumor growth in a diffuse large B cell lymphoma (DLBCL) animal model, through the synergistic effect of both agents (see Figure C below).

Assessment of Potential CD47-related In Vitro and In Vivo Hematologic Effects

First, in a representative flow cytometric analysis (see Figure A below), lemzoparlimab showed minimal binding to human RBCs compared to comparator CD47 antibodies used at the same concentration (1 µg/ml). The minimal binding of lemzoparlimab to RBCs was confirmed when compared with other CD47 antibodies across multiple concentrations in another flow cytometric experiment (see Figure B below).

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Second, as CD47 is expressed on normal RBCs, binding of CD47 antibodies to the surface of RBCs could cross-link the RBCs into lattices and prevent them from precipitating into compact pellets, which is a phenomenon termed hemagglutination. Our results showed that lemzoparlimab did not induce RBC agglutination across a wide range of antibody concentrations, while a comparator antibody caused significant hemagglutination starting at a concentration of 0.3 µg/ml. Results from a representative experiment are shown below.

Thirdly, in vivo safety studies were performed in cynomolgus monkeys to assess the effects of lemzoparlimab on the hematology parameters. Whereas a single bolus IV injection of the comparator antibody caused a significant drop in the number of RBCs and hemoglobin (“HGB”) levels, treatment with lemzoparlimab at a dose of 10 mg/kg did not significantly affect the number of RBCs, HGB levels or reticulocyte or platelet counts (see figure below).

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Moreover, in a four-week GLP toxicology study, lemzoparlimab treatment did not induce significant overall toxicologic changes. Only mild decreases in the number of RBCs, HGB and hematocrit were found, which reached nadir at Day 4 post-first administration and then gradually recovered to the normal range following administration. The changes were not dose-dependent. Compared with the placebo control, the average decrease of RBCs in the treated animals was approximately 6% to 9% with only one animal showing an 18% drop at a dose of 30 mg/kg. No RBC-associated changes were noted in histopathologic examinations or in bone marrow smears (including erythrocytic series). Therefore, NOAEL was defined at 100 mg/kg.

Four-week GLP Toxicology Study in Monkeys

Key preclinical data described above have been published as a poster presentation (#4063) at American Society of Hematology 2019 Annual Meeting.

Clinical Development Plan

The goal of our global and China clinical development plans is to explore the potential in both hematologic malignancies and solid tumor indications, including but not limited to AML/MDS, ovarian cancer and gastric cancer, in both the United States and China.

In September 2020, we received the NMPA approval for a Phase 1 clinical trial of lemzoparlimab in relapsed or refractory advanced lymphoma in China as part of the ongoing international multi-center trial. In addition, lemzoparlimab is being evaluated in a Phase 1/2a clinical trial in China in patients with relapsed or refractory (r/r) AML or MDS, and we anticipate reporting top-line results in early 2021. We have also entered into a clinical trial collaboration and supply agreement with Merck Sharp & Dohme Corp, or MSD, through a subsidiary, under which we will sponsor a Phase 1 clinical trial in the United States evaluating lemzoparlimab in combination with KEYTRUDA^® (pembrolizumab), MSD’s anti-PD-1 therapy, in patients with multiple types of solid tumors. In September 2020, we granted AbbVie a global license, excluding Mainland China, Hong Kong and Macau, to develop and commercialize lemzoparlimab (as well as certain other compounds directed against CD47), and we will retain all rights to develop and commercialize lemzoparlimab in Mainland China, Hong Kong and Macau.

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Uliledlimab (TJD5): A Potential Highly Differentiated CD73 Antibody for Cancer Treatment

Summary

Uliledlimab is an internally developed, humanized inhibitory antibody against human CD73. CD73 is a homodimeric enzyme expressed in tumors and plays a critical role in suppressing immune cells in tumor micro-environment. Uliledlimab displays sub-nanomolar binding affinity to CD73 and inhibits its nucleotidase activity. In vitro, uliledlimab completely reversed the AMP- or tumor cell-mediated suppression of T cells. In vivo, when combined with a PD-L1 antibody, uliledlimab exhibited a superior or synergistic inhibitory effect on tumor growth. The key differentiation of uliledlimab when compared to some of the other clinical stage antibodies of the same class, is related to its novel epitope, which works through a unique intra-dimer binding mode, resulting in a complete inhibition of the enzymatic activity and avoiding the aberrant pharmacological property known as the “hook effect.” With this particular mode of action, uliledlimab, if approved, has the potential to become a highly differentiated CD73 antibody.

We have completed the initial assessment of the clinical trial in the United States as a single agent and in combination with atezolizumab (TECENTRIQR), a PD-L1 antibody marketed by Roche, in patients with advanced solid tumors. Topline results from a clinical study under contract with TRACON show that uliledlimab is safe and well tolerated at the dose range evaluated and demonstrate clinical activity in patients with advanced solid tumors. We are scheduled to submit an abstract to ASCO for the 2021 annual meeting. In China, we are conducting a Phase 1/2 clinical trial to evaluate uliledlimab in patients with advanced solid tumors. The first patient in the single agent study was dosed in May 2020. The first patient in the combination study was dosed on February 3, 2021. This Phase 1/2 study is a multicenter, open-label, dose escalation and cohort expansion study, which will evaluate safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy of uliledlimab, and determine a recommended dose for further planned clinical studies of its efficacy and safety as a single agent and in combination with standard dose of toripalimab (TUOYIR) in patients with advanced or metastatic cancers who are refractory to or intolerant of all available therapies. We have been able to accelerate the Phase 1/2 trial in China by leveraging data from the ongoing Phase 1 clinical study of uliledlimab in the United States, which is a testament to our global clinical development capabilities and well-executed pipeline strategies. In China, we will also collaborate with Shanghai Junshi Biosciences Co., Ltd, or Junshi, for the combination therapy of uliledlimab with Junshi’s PD-1 monoclonal antibody toripalimab in cancer patients with various types of solid tumors.

Therapeutic Options and Current Development

Despite recent breakthroughs with PD-1/PD-L1 therapies, clinical non-response rates to such treatments remains high in cancer patients (exceeding 60%). This non-responsiveness to these standard treatments is partly due to the fact that T cells within an inhibitory tumor environment are suppressed and fail to respond to stimulation induced by PD-1/PD-L1 therapies. CD73, which converts extracellular adenosine monophosphate (“AMP”) to adenosine, is implicated in one of the protective mechanisms of tumors that evade immune attack by creating an adenosine-rich microenvironment inhibitory to immune cells. Pre-clinical studies have indicated that the inhibition of CD73 renders T cells more responsive to PD-1/PD-L1 therapies by altering the tumor micro-environment, resulting in a superior anti-tumor effect. As CD73 is widely expressed in various cancers, a combination therapy of uliledlimab with a PD-1/PD-L1 antibody may increase the likelihood of treatment success in cancer patients who do not respond to standard PD-1/PD-L1 therapies. The potential cancer indications of uliledlimab include thyroid cancer, lung cancer, colorectal cancer, stomach cancer, urothelial cancer, endometrial cancer, head and neck cancer, breast cancer, ovarian cancer, and melanoma, in which CD73 is widely expressed.

A number of global companies are running active clinical development programs with CD73 antibodies. Oleclumab (MEDI-9447) from Medimmune and BMS-986179 from Bristol-Myers Squibb are the two most advanced CD73 antibodies, which are in Phase 2 clinical trials. BMS-986179 is being studied as a single agent and in combination with nivolumab (a PD-1 antibody) for the treatment of advanced colorectal, esophageal,

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gastric, ovarian, and pancreatic cancers. MedImmune is testing MEDI-9447 for the treatment of solid tumors as a single agent or in combination with durvalumab (a PD-L1 antibody) or chemotherapy. NZV-930 (from Novartis) and CPI-006 (from Corvus) have entered Phase 1 clinical trials for the treatment of solid tumors.

Advantages of Uliledlimab

Extracellular AMP can be generated from ATP, cyclic AMP and nicotinamide adenine dinucleotide (“NAD”) through separate biochemical pathways, all of which converge to CD73 to generate adenosine. Thus, CD73 antibody is expected to block adenosine generation more completely than other related targets. Further, CD73 antibody works through a substrate non-competitive fashion and has advantages over small molecule inhibitors targeting the adenosine pathway through a substrate competing fashion. More importantly, uliledlimab, if approved, is potentially highly differentiated among the clinical stage CD73 antibodies as it binds to a novel epitope in the C-terminal domain of CD73 without causing a “hook effect.”

Uliledlimab has the following key advantages: (i) uliledlimab exhibits a typical dose-response curve without the “hook effect” and with a complete inhibition of both soluble and surface-bound CD73 and (ii) uliledlimab has a non-competitive inhibitory effect that is not blunted by high levels of CD73 enzyme substrates, which would be expected for small-molecule competitive blockers. These pharmacological properties may translate into efficient target inhibition in tumors and superior anti-tumor activity, especially in an adenosine-rich micro-environment.

Mechanism of Action

Adenosine is a potent immunosuppressive signaling molecule abundant in the tumor microenvironment. CD73 is the rate-limiting enzyme that generates adenosine from extracellular AMP. Uliledlimab allosterically inhibits the CD73 enzyme by preventing the inactive CD73 dimer from changing into the active conformation in a substrate non-competitive manner. This results in a decrease in adenosine production in the tumor micro-environment, increasing T cell anti-tumor activity.

Summary of Pre-clinical Results

Inhibition of CD73 by Uliledlimab. As shown in the figure below, uliledlimab displayed complete inhibition of soluble CD73 enzymatic activity (IC50= 0.22 nM) without the “hook effect” in contrast to the comparator molecule, which at higher concentrations caused a paradoxical rebound of enzymatic activity presumably due to its inter-dimer binding mode.

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Figure: Inhibition of soluble CD73 enzymatic activity by CD73 antibodies.

Restoration of T Cell Activity by Uliledlimab In Vitro. We observed that AMP inhibited interferon gamma (IFN-g) production by CD4 or CD8 T cells through adenosine generation, mimicking the suppressive tumor microenvironment where AMP is abundantly produced. However, this suppression could be reversed by uliledlimab in a concentration-dependent manner. Moreover, in an experimental system where CD73high human ovarian cell line SK-OV-3 and human T cells were co-cultured, addition of uliledlimab restored T cell activity as measured by IFN-g production in a concentration-dependent manner.

In Vivo Anti-tumor Activity of Uliledlimab. Uliledlimab monotherapy showed a moderate anti-tumor effect in a mouse xenograft model bearing A375 melanoma cells. To examine whether uliledlimab can enhance the anti-tumor activity of the PD-L1 antibody, we evaluated the therapeutic effects of uliledlimab used as a single agent and in combination with a PD-L1 antibody in the same A375 melanoma model. The combination treatment group resulted in 68% inhibition of tumor growth which is significantly better than the vehicle and uliledlimab monotherapy.

Pharmacokinetics of Uliledlimab in Cynomolgus Monkeys. Following a single IV injection of uliledlimab at 5, 25 and 50 mg/kg, the mean C_max ranged dose-proportionally from 136 to 1430 µg/mL, and the systemic exposure indicated by the AUC₀-last increased in a non-linear manner, ranging from 4020 to 135000 hr*µg/mL. Mean half-life was 44.9 hours, 61.5 hours and 104 hours, respectively, reflecting decreased clearance of uliledlimab with increasing dose. No apparent sex difference was observed in the main PK parameters. Positive

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ADAs against uliledlimab were detected in the majority of the animals, without an apparent impact on systemic exposure.

Repeat-dose Toxicology Study of Uliledlimab in Cynomolgus Monkeys. A four-week GLP toxicity study was conducted in cynomolgus monkeys followed by a six-week recovery period to evaluate the potential toxicity of uliledlimab. Forty cynomolgus monkeys were randomly assigned into four groups (5/sex/group) and given five weekly doses of uliledlimab at 20, 60 or 200 mg/kg via IV injection. Systemic exposures (C_max and AUC_0-t) generally increased dose-proportionally, and the Day 22 values were generally higher than those on Day 1, with mean accumulation ratios (AR) ranging between 1.65 and 2.19. No apparent sex difference was observed. Positive uliledlimab antibodies were detected in the majority of animals following repeat administration at all doses, while no significant impact was observed on the TK profiles.

The only uliledlimab-related effect was decreased monocyte chemoattractant protein 1 (MCP-1) on Day 1 (24 or 48 hours post-dosing) in treated animals. Due to a lack of corresponding findings or impact on the well-being of the animals, this effect was not considered adverse. No abnormality was observed in other study endpoints, including safety pharmacology parameters and immunotoxicity. The no observed adverse effect level (NOAEL) was defined at 200 mg/kg. This dose level corresponded to the mean C_max and AUC values of 6890 µg/mL and 594000 µg*hr/mL in males, respectively, and 6450 µg/mL and 501000 µg*hr/mL in females, respectively, on Day 22 of the dosing phase.

Clinical Development Plan

We will develop uliledlimab in the United States and China in parallel. We have completed the initial assessment of the clinical trial in the United States as a single agent and in combination with atezolizumab (TECENTRIQR), a PD-L1 antibody marketed by Roche, in patients with advanced solid tumors. Topline results from a clinical study under contract with TRACON show that uliledlimab is safe and well tolerated at the dose range evaluated and demonstrate clinical activity in patients with advanced solid tumors. We are scheduled to submit an abstract to ASCO for the 2021 annual meeting. In China, we are conducting a Phase 1/2 clinical trial to evaluate uliledlimab in patients with advanced solid tumors. The first patient in the single agent study was dosed in May 2020. The first patient in the combination study was dosed on February 3, 2021. This Phase 1/2 study is a multicenter, open-label, dose escalation and cohort expansion study, which will evaluate safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy of uliledlimab, and determine a recommended dose for further planned clinical studies of its efficacy and safety as a single agent and in combination with standard dose of toripalimab (TUOYIR) in patients with advanced or metastatic cancers who are refractory to or intolerant of all available therapies. We have been able to accelerate the Phase 1/2 trial in China by leveraging data from the ongoing Phase 1 clinical study of uliledlimab in the United States, which is a testament to our global clinical development capabilities and well-executed pipeline strategies.

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Pre-clinical Assets (Monoclonal antibodies)

TJ210 and TJX7 are monoclonal antibodies currently at the pre-clinical stage. The FDA clearance for the IND application of TJ210 was obtained in September 2020.

TJ210: A Potential Highly Differentiated Antibody Targeting Myeloid Derived Suppressor Cells in Cancers and Autoimmune Diseases

TJ210 is a fully human, high affinity antibody against human C5aR1 for the treatment of cancers and potentially autoimmune diseases. Tumors produce large amounts of complement factor C5a to attract C5aR1-expressing myeloid derived suppressor cells (“MDSCs”), M2 macrophages and neutrophils. These myeloid cells critically contribute to an immunosuppressive microenvironment as part of the evading mechanism of tumors and are associated with poor prognosis and resistance to PD-1/PD-L1 therapies in many cancers. Inhibition of C5a or its receptor C5aR in mice leads to markedly reduced MDSCs and has an inhibitory effect on tumor growth in various tumor-bearing animal models. The C5aR-blocking antibody has been shown to have significant therapeutic activity when combined with PD-1 therapies in PD-1-resistant tumor models. TJ210 exerts strong anti-tumor activity by blocking the activation and migration of C5aR1-expressing myeloid cells and has a highly differentiated potential, if approved, as it binds to a novel epitope and possesses superior functional properties. Compared to the only competitor antibody from Innate Pharma, TJ210 shows a more potent anti-tumor effect, especially when C5a concentrations are high, and binds to C5a receptors in both humans and monkeys, making pre-clinical safety assessment possible. In addition, TJ210 has therapeutic potential in multiple inflammatory and autoimmune indications, in which the role of the C5a/C5aR axis has been validated. We partnered with the original developer of TJ210, MorphoSys, for Greater China rights and shared global rights.

In September 2020, the FDA has cleared the IND application for TJ210 to initiate a Phase 1 clinical trial. The trial is designed to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of TJ210 and is expected to commence by early 2021. We plan to work jointly with MorphoSys to develop this asset.

TJX7: A Novel CXCL13 Antibody for Autoimmune Diseases

TJX7 is an internally discovered novel humanized neutralizing antibody targeting the CXCL13 chemokine. CXCL13, through its receptor CXCR5, plays a key role in forming germinal centers, which are critical for immune response. The role of CXCL13 in forming germinal centers is to guide the migration of germinal center B cells and follicular T cells within the lymphoid organs and facilitate their interaction, maturation and function. One of the key pathogenic features in autoimmune diseases is related to the aberrant formation of ectopic germinal centers formed in affected organs, contributing to chronic inflammation and tissue destruction. Elevated serum CXCL13 levels, CXCR5-expressing T cells and pathogenic germinal center B cells and even ectopic germinal center formation are found in multiple autoimmune diseases, including Sjögren’s syndrome, RA, multiple sclerosis, and SLE. TJX7 is being developed for the treatment of autoimmune disorders and has been shown to bind to CXCL13 with sub-nanomolar affinity, effectively blocking the interaction between CXCL13 and CXCR5 and the downstream signaling. TJX7 has been shown to completely inhibit the migration of primary human tonsil B cells. Pharmacodynamic studies in mice and cynomolgus monkeys have confirmed TJX7’s inhibitory effects on germinal center formation and antibody production. Results generated so far indicate that TJX7 may provide a new therapeutic angle in the treatment of autoimmune diseases as it acts uniquely at the core of tissue pathologies. TJX7 is currently under CMC and pre-clinical development.

Pre-clinical Assets (Bi-Specific Antibody Panel)

PD-L1-based Bi-specific Antibodies. As previously discussed, this panel of PD-L1-based bi-specific antibodies is designed according to the scientific rationale that a PD-L1 antibody, when engineered with a selected second immune component such as a cytokine or another antibody, is able to convert “cold tumors,” which typically do not respond to PD-1/PD-L1 inhibitors, to “hot tumors,” which are more sensitive to PD-1/PD-

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L1 therapies. Such PD-L1-based bi-specific antibodies are expected to increase the probability of treatment success in patients who do not respond to PD-1/PD-L1 treatment. Based on this concept, we have generated a panel of bi-specific antibodies using our proprietary PD-L1 antibody sequence as the backbone (the first signal), linked to a second component (the second signal) of selected immune properties. Representative examples of the second signals for this panel of bi-specific antibodies include IL-7 cytokine (expanding T effector cells), 4-1BB and B7-H3 antibodies (activating T cells synergistically with PD-L1) and CD47 antibody (adding the macrophage killing mechanism). We strive to validate all bi-specific antibodies through a series of robust in vitro and in vivo studies for proof-of-concept, thus providing a solid basis for further development. Collectively, we have demonstrated that the second paired component must be structurally integrated with the tumor-engaging anti-PD-L1 backbone to concentrate and function effectively inside tumors, which cannot be achieved by simply combining two free agents.

“Fortified” Bi-specific Antibodies for Specific Cancer Therapeutic Purposes. TJ-C4GM is a “fortified” version of the CD47 antibody, which is specifically designed for the treatment of solid tumors through the CD47-mediated macrophage killing mechanism. As the majority of tumor-associated macrophages adopt an anti-inflammatory and tumor-promoting M2 phenotype rather than a pro-inflammatory M1 phenotype, they are less efficient in phagocytosis in response to CD47 blockade. Thus, treatment of solid tumors with the CD47 antibody may exhibit limited efficacy. TJ-C4GM is a novel molecule composed of lemzoparlimab with an engineered GM-CSF moiety fused at the C-terminus of the antibody heavy chain. GM-CSF is a potent cytokine known to convert tumor-resident M2 macrophages into tumor-engulfing M1 macrophages, which enables TJ-C4GM to exert a better phagocytic effect in solid tumors. These unique functional properties of TJ-C4GM are confirmed in a series of in vitro and in vivo tumor animal models, in which TJ-C4GM exerts superior anti-tumor activity against solid tumors, which cannot be achieved by lemzoparlimab or GM-CSF used either alone or in combination. TJ-C4GM is currently at the CMC and pre-clinical development stage.

TJ-CLDN4B is a bi-specific antibody targeting both Claudin18.2 (CLDN18.2), a tumor antigen preferentially expressed in gastric and pancreatic cancers, and 4-1BB, a co-stimulatory molecule on T cells. CLDN18.2 is a tight junction molecule normally expressed only on epithelial cells of the gastric mucosa, which is inaccessible by antibodies under normal conditions, making it a highly attractive tumor target. Although a CLDN18.2 monoclonal antibody (claudiximab) was active in a Phase 2 trial, only the CLDN18.2 high-expressing tumors seemed to be susceptible. In collaboration with ABL Bio, we developed a bi-specific antibody, TJ-CLDN4B, which provides two key advantages over current CLDN18.2 antibodies and 4-1BB agonistic antibodies. First, TJ-CLDN4B is capable of binding to tumor cells even with low levels of CLDN18.2 expression, making it more suitable for a broader patient population. Second, only upon tumor cell engagement by TJ-CLDN4B are T cells activated. In contrast, other pan-activating 4-1BB antibodies that activate T cells regardless of tumor engagement are prone to liver toxicity as seen in clinical studies. In a humanized mouse model, TJ-CLDN4B suppressed tumor growth to a greater extent than anti-CLDN18.2 or anti-4-1BB alone or in combination. TJ-CLDN4B is currently at the CMC and pre-clinical development stage. We expect to file an IND for a first-in-human clinical study with the FDA in the first quarter of 2021.

Licensing and Collaboration Arrangements

A. In-Licensing Arrangements

Licensing Agreement with MorphoSys (Felzartamab)

In November 2017, we entered into a license and collaboration agreement with MorphoSys AG (“MorphoSys”) with respect to the development and commercialization of felzartamab (MOR202/TJ202), MorphoSys´s proprietary investigational antibody against CD38 (the “CD38 product”).

Under this agreement, MorphoSys granted to us an exclusive, royalty-bearing, sublicensable license to exploit MOR202/TJ202 for any human therapeutic or diagnostic purpose in the licensed territory, namely Greater China.

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Pursuant to this agreement, we granted to MorphoSys an exclusive license to our rights in any inventions that we make while exploiting MOR202/TJ202 under this agreement, solely to exploit MOR202/TJ202 outside of Greater China.

We also received the right to sublicense to affiliates and third parties acting as contract manufacturers, contract research organizations, distributors or wholesalers without prior written consent, as well as the right to sublicense to other third parties with the prior written consent of MorphoSys, not to be unreasonably withheld, delayed or conditioned.

We are solely responsible for the development and commercialization of MOR202/TJ202 in Greater China, and must use commercially reasonable efforts as we develop and commercialize MOR202/TJ202.

Pursuant to this agreement, we paid to MorphoSys an upfront license fee of US$20.0 million. We also agreed to make milestone payments to MorphoSys, conditioned upon the achievement of certain development, regulatory and commercial milestones, in the aggregate amount of US$98.5 million. Such milestones include first patient dosed in human clinical trials, marketing approval, and first annual net sales of CD38 products covered by the agreement in excess of a certain amount. As of the date of this prospectus supplement, we have made milestone payments of US$8.0 million to MorphoSys.

In addition, we are required to pay tiered low-teens royalties to MorphoSys on a country-by-country and product-by-product basis during the term, commencing with the first commercial sale of a relevant licensed product in Greater China. The end of the royalty term is linked to (i) the expiration, invalidation or abandonment of relevant patent claims, (ii) 10 years from the date of first commercial sale of such CD38 product, and (iii) marketing exclusivity for such relevant licensed product. To date, we have not paid any royalties to MorphoSys. Unless terminated earlier in accordance with the terms thereof, this agreement will remain in effect until the expiration of our last payment obligation under the agreement. This agreement may be terminated by either party for the other party’s uncured material breach, bankruptcy or insolvency. In addition, we have the right to terminate the agreement for convenience at any time after a certain specified time period upon a notice period that varies based upon the stage of development. MorphoSys has the right to terminate the agreement if we challenge its patents. To the extent that we terminate for convenience or MorphoSys terminates for our material breach, bankruptcy, insolvency or patent challenge, among other things, all licenses and rights granted by MorphoSys to us will automatically terminate and the licenses and rights granted by us to MorphoSys will survive. In the event of such termination, we must also grant to MorphoSys an exclusive, royalty-bearing, sublicensable license under certain of our intellectual property relating to the licensed product to exploit MOR202/TJ202 for any human therapeutic or diagnostic purpose in Greater China.

Assignment and License Agreement with Genexine (Eftansomatropin)

In October 2015, I-Mab Bio-tech Tianjin Co., Ltd., known as Tasgen Bio-tech (Tianjin) Co., Ltd. at the time (which subsequently became our subsidiary following the Acquisition) (“I-Mab Tianjin”), entered into an intellectual property assignment and license agreement with Genexine, Inc. (“Genexine”), further amended in December 2017, with respect to four licensed products, namely GX-H9 (TJ101), GX-G3 (TJ102), GX-G8 and GX-P2 and one assigned product, GX-G6 (TJ103). Under this agreement, Genexine (i) granted to I-Mab Tianjin an exclusive, non-transferable, sublicensable license to use and otherwise exploit certain intellectual property to engage in pre-clinical and clinical development, manufacturing, sale and distribution of the above-mentioned licensed products for (A) the treatment of any disease with respect to GX-H9 and GX-G3 in China (which, for clarity excludes, Hong Kong, Macau and Taiwan), (B) the treatment of chemically induced diarrhea, with respect to GX-G8 anywhere in the world and (C) the treatment of rheumatoid arthritis and lupus (not including psoriasis) with respect to GX-P2 anywhere in the world and further (ii) assigned to I-Mab Tianjin a certain Chinese patent and related know-how related to the assigned product (TJ103) and granted I-Mab Tianjin an exclusive license to exploit the assigned intellectual property to engage in pre-clinical and clinical development, manufacturing, sale and distribution of the assigned product (TJ103) for the treatment of any disease in China (which, for clarity,

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excludes Hong Kong, Macau and Taiwan). I-Mab Tianjin will also receive an exclusive license to any improvements that Genexine develops or acquires related to any of the aforementioned products.

Under this agreement, I-Mab Tianjin paid an aggregate upfront license fee of US$13.0 million in relation to the patents, patent applications, know-how, data and information in connection with the four licensed products and a purchase fee of US$7.0 million in connection with the assigned product (TJ103). I-Mab Tianjin also agreed to make certain milestone payments, including milestone payments in the aggregate amount of US$40.0 million for GX-H9, US$25.0 million for TJ103 and US$15.0 million for GX-G3, conditioned upon the achievement of certain net sales targets. As of the date of this prospectus supplement, we have made upfront license payment of US$0.1 million and milestone payments of US$0.9 million to Genexine.

The term of this agreement is 30 years unless terminated earlier in accordance with the terms thereof. This agreement may be terminated by either party for the other party’s uncured material breach, bankruptcy or insolvency, in the event of force majeure or a PRC regulatory requirement to make material alteration or modification to the contractual rights or obligations of this agreement which has the effect of preventing the parties from achieving their business objectives, or upon the termination of a certain subscription agreement or a certain joint venture agreement entered into by I-Mab Tianjin and Genexine in October 2015 (provided that the termination of such subscription agreement or joint venture agreement was not due to the material breach of the party electing to terminate this agreement). Genexine has the right to terminate the agreement if we fail to use commercially reasonable efforts to obtain regulatory approvals for commercializing the licensed product in the agreed period due to our own fault or if we cease to pursue clinical development or product registration or to conduct licensed activities on a reasonable scale as approved by our board of directors. During the term of this agreement, if I-Mab Tianjin develops or acquires any improvement, modification or alteration to the licensed products, I-Mab Tianjin will become the sole legal owner of such improvements, modifications and alterations and has full power, right and authority to grant licenses or transfer ownership of the same. I-Mab Tianjin is required to promptly notify Genexine in writing giving details of any such improvements, modifications or alterations and provide Genexine with such explanations or trainings to enable Genexine to legally and effectively use the same. Additionally, I-Mab Tianjin shall grant to Genexine a fully paid up, royalty-free, exclusive license to use any such improvements, modifications and alterations anywhere outside of the territory for which I-Mab Tianjin is licensed under this agreement.

Licensing Agreement with Genexine (GX-I7/TJ107)

In December 2017, we entered into an intellectual property license agreement with Genexine with respect to GX-I7, a long-acting IL-7 cytokine. Under this agreement, Genexine granted to us an exclusive, sublicensable and transferable license to use and otherwise exploit certain intellectual property (including improvements subsequently developed or acquired by Genexine) in connection with the pre-clinical and clinical development, manufacturing, sale and distribution of GX-I7 to treat cancers in the field of oncology in China, Hong Kong, Macau and Taiwan.

Under this agreement, we paid an upfront license fee of US$12.0 million to Genexine. We also agreed to make milestone payments in the aggregate amount of US$23.0 million, conditioned upon the achievement of certain development milestones, including completion of Phase 2 and Phase 3 clinical studies and NDA or BLA approval in any of China, Hong Kong, Macau or Taiwan.

Further, we agreed to make milestone payments in the aggregate amount of US$525.0 million, conditioned upon the achievement of certain cumulative net sales of GX-I7 up to US$2,000 million. We also are required to pay Genexine a low-single-digit percentage royalty in respect of the total annual net sales of GX-I7. The aforesaid milestones and royalties (other than the upfront payment) will be reduced by 50% following the entry of a generic version of GX-I7 in China, Hong Kong, Macau and Taiwan without the consent or authorization of us or any of our sublicensees. As of the date of this prospectus supplement, no milestone payments or royalties are due under this agreement.

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