As Amgen advances its bid to join the first wave of biosimilars to Bristol Myer Squibb and Ono Pharmaceutical’s oncology megablockbuster Opdivo, the originator drug’s partners are not taking the challenge lying down.
In a lawsuit made public this week, BMS and Ono are suing Amgen in Delaware over claims that its proposed biosimilar would tread on a number of patents for Opdivo (nivolumab)—a PD-1 inhibitor that has scooped up many cancer indications since its original 2014 nod in advanced melanoma, generating more than $5.9 billion in U.S. revenue alone last year.
Across all geographies, the medicine rounded up (PDF) sales of more than $10 billion in 2025, growing 8% year over year.
In their lawsuit, BMS and Ono accuse Amgen of aiming to market its biosimilar ahead of the expiration of key U.S. patents covering Opdivo’s active ingredient and method of treatment. The lawsuit alleges infringement of seven Opdivo patents, known colloquially as the ‘449, ‘320, ‘082, ‘154, ‘107, ‘153 and ‘917 patents.
In turn, Bristol and Ono hope to win orders enjoining Amgen from manufacturing or selling its biosimilar version of Opdivo while the partners’ patents remain in place.
According to BMS’ latest annual report, the company has set (PDF) an estimated minimum market entry date for U.S. Opdivo copycats in 2028.
In a statement, an Amgen spokesperson told Fierce that the company cannot comment directly on pending litigation but stressed that it “remains confident that ABP 206 will be in the first wave of Opdivo biosimilars,” referring to its investigational product by its code name.
The spokesperson confirmed that Amgen has submitted its Opdivo biosimilar application to the FDA, with a decision now expected “by the end of the year,” adding that “Amgen has a long track record of successfully developing and delivering high-quality biosimilars for patients.”
BMS, for its part, did not immediately respond to Fierce’s request for comment.
The partners’ complaints in large part seem to hinge on what they feel was inadequate correspondence from Amgen during the process biosimilar developers must go through when plotting for approval.
In particular, lawyers for BMS and Ono allege that Amgen “purported to comply” with its obligation to hand over information to BMS—used to determine whether the program might tread on the originator medicine’s patents—after which Bristol “promptly identified and requested missing Amgen information” that it needed to fully assess the proposed biosimilars intellectual property impact.
The lawsuit notes that BMS specifically “identified missing details of Amgen’s manufacturing process that were necessary to determine whether Amgen intended to use innovations for which plaintiffs had secured patents.”
The filing goes on to detail a back-and-forth between the rivals over details and disagreements that ultimately culminated in the litigation made public this week.
In another potential extension for Opdivo’s branded lifespan, BMS last year scored approval for a subcutaneous version of the med, dubbed Opdivo Qvantig, which co-formulates nivolumab with recombinant human hyaluronidase.
That patent extension strategy has also been pursued by PD-1/L1 developers like Roche and Merck & Co.