Bristol-Myers Sues Amgen Over Proposed Opdivo Biosimilar

Bristol-Myers Squibb Co. has filed a complaint against Amgen Inc.'s proposed biosimilar, ABP 206, alleging that it infringes on seven patents related to Opdivo, a blockbuster cancer drug.

The lawsuit was initially filed under seal on September 8 and a redacted version was filed in the US District Court for the District of Delaware on Monday. The complaint aims to protect key uses of Opdivo, which had sales of $5.9 billion in 2025, accounting for 12.25% of Bristol-Myers' overall revenue.

Bristol-Myers is betting that later-expiring treatment patents can preserve protection for the drug years after its foundational patent's expiration.