I-Mab Announces Authorization of a Renewed Stock Repurchase Program by the Company up to US$40 Million

SHANGHAI and GAITHERSBURG,Md.,July 29,2021 -- I-Mab (the "Company") (Nasdaq: IMAB),a clinical stage biopharmaceutical company committed to the discovery,development and commercialization of novel biologics,today announced that its Board of Directors (the "Board") has authorized a new stock repurchase program. With the Board's authorization,the Company may repurchase up to US$40 million of its ordinary shares in the form of American depositary shares ("ADS") over the next 12 months.

In July 2020,the Board first authorized a stock repurchase program under which the Company may repurchase up to US$20 million of its ordinary shares in the form of ADS over a 12-month period. The renewed stock repurchase program now has an increased cap of US$40 million.

"We are pleased that the Board has authorized this new stock repurchase program by the Company." said Dr. Jingwu Zang,Founder and Chairman of I-Mab,"The Company's fundamentals remain very strong and the authorization demonstrates the confidence we have in our globally competitive innovative pipeline and our journey to becoming a fully integrated global biopharma."

Repurchases,if any,under the program will be made at the discretion of management,and will depend upon market pricing and conditions,business,legal,accounting and other considerations. Any such share purchases will be made by the Company from time to time in open market transactions,or otherwise in compliance with Rule 10b-18 under the Securities Exchange Act of 1934,or pursuant to a trading plan adopted in accordance with Rule 10b5–1 of the Securities Exchange Act of 1934.

The repurchase program is effective upon and from the date on which a formal stock repurchase plan engagement agreement is signed with a qualified broker-dealer(s),and terminates over a twelve-month period depending upon market and economic conditions,and other factors including price,legal and regulatory requirements and capital availability. The program does not obligate I-Mab to acquire any particular number of its ADSs,and the program may be modified or suspended at any time at the management's discretion.

About I-Mab

I-Mab (Nasdaq: IMAB) is a dynamic,global biotech company exclusively focused on discovery,development and soon,commercialization of novel or highly differentiated biologics in the therapeutic areas of immuno-oncology and autoimmune diseases. The Company's mission is to bring transformational medicines to patients around the world through innovation. I-Mab's innovative pipeline of more than 10 clinical and pre-clinical stage drug candidates is driven by the Company's Fast-to-PoC (Proof-of-Concept) and Fast-to-Market development strategies through internal R&D and global partnerships. The Company is on track to transition from a clinical stage biotech company toward a fully integrated global biopharmaceutical company with cutting-edge R&D capabilities,world-class GMP manufacturing facilities and commercial capability. I-Mab has offices in Beijing,Shanghai,Hangzhou,Hong Kong and Maryland,United States. For more information,please visit http://ir.i-mabbiopharma.com and follow I-Mab on LinkedIn,Twitter and WeChat.

I-Mab Forward Looking Statements

This announcement contains forward-looking statements. These statements are made under the "safe harbor" provisions of the U.S. Private Securities Litigation Reform Act of 1995. These forward-looking statements can be identified by terminology such as "will," "expects," "anticipates," "future," "intends," "plans," "believes," "estimates," "confident" and similar statements. I-Mab may also make written or oral forward-looking statements in its periodic reports to the U.S. Securities and Exchange Commission (the "SEC"),in its annual report to shareholders,in press releases and other written materials and in oral statements made by its officers,directors or employees to third parties. Statements that are not historical facts,including statements about I-Mab's beliefs and expectations,are forward-looking statements. Forward-looking statements involve inherent risks and uncertainties. A number of factors could cause actual results to differ materially from those contained in any forward-looking statement,including but not limited to the following: I-Mab's ability to demonstrate the safety and efficacy of its drug candidates; the clinical results for its drug candidates,which may not support further development or NDA/BLA approval; the content and timing of decisions made by the relevant regulatory authorities regarding regulatory approval of I-Mab's drug candidates; I-Mab's ability to achieve commercial success for its drug candidates,if approved; I-Mab's ability to obtain and maintain protection of intellectual property for its technology and drugs; I-Mab's reliance on third parties to conduct drug development,manufacturing and other services; I-Mab's limited operating history and I-Mab's ability to obtain additional funding for operations and to complete the development and commercialization of its drug candidates; and the impact of the COVID-19 pandemic on the Company's clinical development,commercial and other operations,as well as those risks more fully discussed in the "Risk Factors" section in I-Mab's most recent annual report on Form 20-F,as well as discussions of potential risks,uncertainties,and other important factors in I-Mab's subsequent filings with the U.S. Securities and Exchange Commission. All forward-looking statements are based on information currently available to I-Mab,and I-Mab undertakes no obligation to publicly update or revise any forward-looking statements,whether as a result of new information,future events or otherwise,except as may be required by law.

For more information,please contact:

I-Mab

Jielun Zhu,Chief Financial Officer

E-mail: jielun.zhu@i-mabbiopharma.com

Office line: +86 21 6057 8000

Gigi Feng,Chief Communications Officer

E-mail: gigi.feng@i-mabbiopharma.com

Office line: +86 21 6057 5709

Investor Inquiries:

The Piacente Group,Inc.

Emilie Wu

E-mail: emilie@thepiacentegroup.com

Office line: + 86 21 6039 8363

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