Bristol Myers sues Amgen over proposed Opdivo biosimilar

Merck & Co

15/09/2026 18:28

By Blake Brittain
Sept 15 (Reuters) - Bristol Myers Squibb BMY.N and Ono Pharmaceutical 4528.T have sued Amgen AMGN.O in Delaware federal court, seeking to block Amgen's proposed U.S. biosimilar of their blockbuster cancer immunotherapy drug Opdivo.
The lawsuit, filed last week and made public on Monday, alleges that Amgen's biosimilar would infringe several patents.
Opdivo earned Bristol Myers more than $5.9 billion in revenue in the United States last year, according to a company report.
An Amgen spokesperson on Tuesday declined to comment on the complaint, citing pending litigation.
Spokespeople for Bristol Myers and Ono did not immediately respond to requests for comment.
Biosimilars are based on existing versions of biologic drugs and are comparable to generic versions of traditional pharmaceuticals. Unlike traditional drugs, complex biologics are made from living cells and cannot be copied exactly.
Bristol Myers and Ono, which co-developed Opdivo, allege that Amgen's biosimilar would infringe seven U.S. patents covering the drug, and asked the court to block sales of the biosimilar while their patents remain in force.
Opdivo has been approved in the U.S. to treat advanced or metastatic cancers, including ​melanoma, non-small cell lung cancer and kidney cancer.
Bristol Myers and Ono settled a patent dispute with Merck in 2017 over its rival blockbuster cancer drug Keytruda. Under the settlement, Merck agreed to pay $625 million and a share of Keytruda royalties through 2023.
Bristol Myers said in a report filed with the U.S. Securities and Exchange Commission in February that it expects to maintain patent exclusivity over Opdivo until 2028.
The case is Bristol-Myers Squibb Co. v. Amgen Inc., U.S. District Court for the District of Delaware, No. 1:26-cv-01134.
For BMS and Ono: Steven Maslowski of Akin Gump Strauss Hauer & Feld
For Amgen: attorney information not yet available

(Reporting by Blake Brittain in Washington)