Bristol Myers Squibb and Ono Pharmaceutical have filed a lawsuit against Amgen over its proposed biosimilar to the cancer immunotherapy Opdivo, escalating a patent dispute as the U.S. Food and Drug Administration prepares to decide on Amgen’s application.
- BMS and Ono are seeking to prevent Amgen from launching its proposed Opdivo biosimilar in the U.S.
- The companies allege that Amgen’s product infringes seven patents associated with Opdivo.
- Amgen has submitted its biosimilar application to the FDA and expects a regulatory decision by the end of 2026.
- Amgen’s candidate, known as ABP 206, is being developed as a biosimilar to nivolumab, the active ingredient in Opdivo.
- BMS estimates that U.S. entry of Opdivo biosimilars could begin in 2028.
Lawsuit Targets Amgen’s Opdivo Biosimilar
The legal dispute centers on Amgen’s ABP 206, a proposed biosimilar to Opdivo (nivolumab), one of BMS and Ono’s leading oncology products.
BMS and Ono filed the case in the U.S. District Court for the District of Delaware, alleging that Amgen’s proposed product would infringe seven patents covering Opdivo. The patents include the so-called ‘449, ‘320, ‘082, ‘154, ‘107, ‘153 and ‘917 patents.
The companies are seeking court orders that would prevent Amgen from manufacturing or selling the biosimilar while the relevant patents remain in force. The lawsuit is part of a broader patent strategy surrounding the expected arrival of biosimilar versions of Opdivo in the U.S.
Opdivo Remains a Major Revenue Driver
Opdivo is a PD-1 immune checkpoint inhibitor that has been approved for a range of cancer indications since its initial approval in 2014 for advanced melanoma.
The drug generated more than $5.9 billion in U.S. revenue in 2025, according to Fierce Pharma, while global sales exceeded $10 billion during the year. Those sales make the product an important source of revenue for BMS as competition from biosimilars approaches.
BMS has previously estimated that the earliest U.S. market entry for Opdivo biosimilars could occur in 2028, although the timing will depend on regulatory, patent and litigation developments.
BMS Raises Questions Over Amgen’s Patent Information
The lawsuit also focuses on information exchanged between the companies during the biosimilar development and patent-disclosure process.
According to the complaint, BMS and Ono contend that Amgen did not initially provide all of the information the originator companies believed was necessary to assess whether ABP 206 would rely on technologies covered by their patents.
BMS alleges that it subsequently identified missing details concerning Amgen’s manufacturing process and requested additional information. The dispute over those disclosures ultimately contributed to the litigation now before the Delaware court.
The allegations have not been resolved by the court, and Amgen has not publicly commented on the specific claims because the litigation is pending.
FDA Decision Expected Before the End of 2026
Separate from the patent case, Amgen has advanced ABP 206 through the FDA approval process.
An Amgen spokesperson told Fierce Pharma that the company has submitted its Opdivo biosimilar application to the FDA and expects a decision by the end of 2026. Amgen said it remains confident that ABP 206 will be among the first wave of Opdivo biosimilars.
Amgen has previously reported positive development progress for ABP 206. Its 2026 proxy materials said a comparative clinical study in patients with resected stage III or IV melanoma met its primary endpoint for pharmacokinetic similarity, while another comparative study in treatment-naive patients with unresectable or metastatic melanoma had completed enrollment.
Patent Dispute Could Shape Launch Timing
FDA approval and commercial availability are separate issues in the U.S. biosimilar market. Even if ABP 206 receives regulatory approval, patent litigation can affect when a biosimilar can actually enter the market.
BMS and Ono’s lawsuit therefore represents an effort to address potential competition before Amgen’s product reaches the market. The companies argue that several patents remain relevant to Opdivo and its uses, while Amgen is seeking to establish a position among the first potential biosimilar entrants.
The dispute comes as biosimilar developers increasingly prepare for the loss of exclusivity surrounding high-value biologic medicines. The FDA has also been working to streamline biosimilar development, including guidance issued in March 2026 that sought to reduce unnecessary pharmacokinetic testing requirements when scientifically justified.
Opdivo’s Franchise Continues to Expand
BMS has also pursued additional formulations and indications to extend the Opdivo franchise. In 2025, the company received FDA approval for Opdivo Qvantig, a subcutaneous formulation combining nivolumab with recombinant human hyaluronidase.
Such product extensions can provide additional options for patients and healthcare providers while also creating new intellectual property considerations around established biologic medicines.
The strategy is not unique to BMS. Other developers of major PD-1 and PD-L1 therapies, including Roche and Merck, have pursued similar approaches as their flagship immunotherapies approach patent and exclusivity milestones.
The immediate developments to watch are the Delaware patent case and the FDA’s review of ABP 206.
A regulatory approval would establish that the FDA has determined the product meets the applicable biosimilar requirements, but it would not by itself resolve the patent claims brought by BMS and Ono.
The timing of any eventual U.S. launch will therefore depend on the outcome of the patent litigation and other applicable exclusivity and patent considerations. For now, Amgen is positioning ABP 206 for a potential first wave of Opdivo biosimilars, while BMS and Ono are seeking to protect the market position of the original product.
Opdivo is facing a potential biosimilar challenge from Amgen as Bristol Myers Squibb (BMS) and Ono Pharmaceutical move to defend patents covering the blockbuster cancer immunotherapy. The companies filed a patent lawsuit against Amgen in Delaware as the FDA review of Amgen’s proposed Opdivo biosimilar approaches.
Opdivo Patent Dispute With Amgen
The dispute centers on Amgen’s investigational Opdivo biosimilar, known as ABP 206. BMS and Ono allege that Amgen’s proposed product would infringe several U.S. patents associated with Opdivo. The lawsuit was filed in the U.S. District Court for the District of Delaware.
BMS and Ono are seeking legal orders that would prevent Amgen from manufacturing or selling the proposed biosimilar while the relevant patents remain in force. The case involves seven patents identified in the companies’ complaint.
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