Bristol Myers Sues Amgen Over Opdivo Biosimilar Patents

Key Facts

1Bristol Myers Squibb and Ono Pharmaceutical filed a lawsuit against Amgen to block a proposed biosimilar version of the cancer drug Opdivo.

2Opdivo generated over $5.9 billion in U.S. revenue for Bristol Myers last year.

3Bristol Myers expects to maintain patent exclusivity for Opdivo until 2028.

In a move to protect one of its most critical revenue streams, Bristol Myers Squibb and Ono Pharmaceutical have filed a lawsuit against Amgen to block a proposed biosimilar version of the cancer drug Opdivo. The plaintiffs are seeking to prevent Amgen from marketing a cheaper alternative, claiming patent infringement. Bristol Myers expects to maintain its patent exclusivity for the drug until 2028, a vital period given that Opdivo generated over $5.9 billion in U.S. revenue last year.

Per market data, Amgen (AMGN) shares closed at $381.5 on September 14, 2026, while Ono Pharmaceutical (4528.T) closed at 2,337.5 JPY on the same date. This litigation highlights the ongoing tension in the pharmaceutical sector between innovative drug makers and biosimilar producers. The outcome is significant for Bristol Myers as it seeks to defend its market share against Amgen's entry into the blockbuster oncology space.

Traders should monitor the Delaware federal court proceedings for any rulings that could impact the timeline for biosimilar entry. While the current economic calendar shows no immediate sector-specific catalysts, the broader market remains sensitive to recent inflation and growth data, which continues to influence the valuation of large-cap biotech and pharmaceutical equities.