The U.S.-listed shares of I-Mab jumped 18.8% to $42.5 before the opening bell.
The agreement is the latest push by AbbVie into cancer therapies after its June collaboration with Denmark's biotech firm Genmab AS to co-develop and market cancer drugs.
AbbVie will pay an additional $1.74 billion in milestone payments for lemzoparlimab, the companies said, adding that I-Mab will retain the rights to sell the drug in China.
I-Mab, which started trading on the Nasdaq at the start of the year, is a biotech company that develops treatments for immuno-oncology and autoimmune diseases.
The companies said they will also work together in future drug trials relating to multiple cancers.
(Reporting by Trisha Roy in Bengaluru; Editing by Arun Koyyur)
