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Patent Dispute Between Daiichi Sankyo and Seagen has Concluded

March 09, 2026

Tokyo – (March 10, 2026) – On December 2, 2025 the U.S. Court of Appeals for the Federal Circuit (the Federal Circuit) reversed a decision from the U.S. District Court for the Eastern District of Texas that found Seagen Inc.’s U.S. Patent No. 10,808,039 (the ’039 patent) not invalid. In view of the reversal, the Federal Circuit vacated the Texas court’s related infringement judgment and damages award against Daiichi Sankyo. In a separate decision on the same day, the Federal Circuit also dismissed as moot Seagen Inc.’s appeal from the U.S. Patent and Trademark Office’s January 2024 Final Written Decision that invalidated all challenged claims of the ’039 patent, which Daiichi Sankyo had challenged in a post-grant review proceeding (PGR).

On March 2, 2026, the deadlines for the parties to seek review of these decisions passed, thereby concluding this dispute.

About Daiichi Sankyo
Daiichi Sankyo is an innovative global healthcare company contributing to the sustainable development of society that discovers, develops and delivers new standards of care to enrich the quality of life around the world. With more than 120 years of experience, Daiichi Sankyo leverages its world-class science and technology to create new modalities and innovative medicines for people with cancer, cardiovascular and other disease with high unmet medical need. For more information, please visit www.daiichisankyo.com.
 

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