The ADS Offering is being made only by means of a prospectus supplement and the accompanying prospectus included in an automatic shelf registration statement on Form F-3 filed with the U.S. Securities and Exchange Commission (the "SEC") on February 5, 2021, which automatically became effective upon filing. The registration statement on Form F-3 and the preliminary prospectus supplement dated February 5, 2021 are available on the SEC website at: http://www.sec.gov. The final prospectus supplement will be filed with the SEC and will be available on the SEC's website at: http://www.sec.gov. When available, copies of the final prospectus supplement and the accompanying prospectus relating to the offering may also be obtained by contacting BofA Securities, Inc., Attention: Prospectus Department, NC1-004-03-43, 200 North College Street, 3rd floor, Charlotte NC 28255-0001, or by emailing [email protected]; Piper Sandler & Co., Prospectus Department, 800 Nicollet Mall, J12S03, Minneapolis, MN 55402, by telephone: (800) 747-3924, or by email: [email protected]; and Cantor Fitzgerald & Co., Attention: Equity Capital Markets, 499 Park Avenue, 6th Floor, New York, New York, 10022 or by email at [email protected].

I-Mab (Nasdaq: IMAB) is an innovation-driven global biotech company focusing on discovery, development and soon commercialization of novel and highly differentiated biologics in immuno-oncology therapeutic area. The Company's mission is to bring transformational medicines to patients around the world through drug innovation. I-Mab's globally competitive pipeline of more than 15 clinical and pre-clinical stage drug candidates is driven by its internal R&D capability and global licensing partnerships, based on the Company's unique Fast-to-Proof-of-Concept and Fast-to-Market pipeline development strategies. The Company is now rapidly progressing from a clinical stage biotech company to a fully integrated global biopharmaceutical company with cutting-edge global R&D capabilities, a world-class GMP manufacturing facility and commercialization capability. I-Mab has established its global footprint in Shanghai (headquarters), Beijing, Hangzhou and Hong Kong in China, and Maryland and San Diego in the United States. For more information, please visit http://ir.i-mabbiopharma.com and follow I-Mab on LinkedIn, Twitter and WeChat.

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. Statements that are not historical facts, including statements about I-Mab's beliefs and expectations, are forward-looking statements. These forward-looking statements can be identified by terminology such as "will," "expects," "anticipates," "future," "intends," "plans," "believes," "estimates" and similar 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. Further information regarding these and other risks is included in I-Mab's filings with the SEC. All information provided in this press release is as of the date of this press release, and I-Mab does not undertake any obligation to update any forward-looking statement, except as required under applicable law.

Jielun Zhu, CFO
E-mail: [email protected]
Office line: +86 21 6057 8000

Gigi Feng, Chief Communication Officer
E-mail: [email protected]
Office line: +86 21 6057 5785

The Piacente Group, Inc.
Emilie Wu
E-mail: [email protected]
Office line: +86 21 6039 8363