Bristol Myers Sues Amgen Over Proposed Opdivo Biosimilar

Bristol Myers Squibb and Ono Pharmaceutical have filed a lawsuit against Amgen in Delaware federal court to block the proposed US launch of an Opdivo biosimilar. The lawsuit alleges that Amgen's biosimilar would infringe on seven US patents covering the drug, which was developed by Bristol Myers and Ono.

Opdivo earned over $5.9 billion in revenue for Bristol Myers in the United States last year, according to a company report. The companies claim that Amgen's biosimilar would violate their patent exclusivity, which they expect to maintain until 2028.

An Amgen spokesperson declined to comment on the lawsuit but stated that the company has applied for FDA approval of its drug and remains confident in its ability to be among the first wave of Opdivo biosimilars. The case is Bristol-Myers Squibb Co. v. Amgen Inc., U.S. District Court for the District of Delaware, No. 1:26-cv-01134.