Daiichi wins Enhertu patent dispute with Seagen

On December 2, the US Court of Appeals for the Federal Circuit (the Federal Circuit) reversed a decision from the US District Court for the Eastern District of Texas that found Pfizer (NYSE: PFE) subsidiary Seagen’s US Patent No 10,808,039 (the ’039 patent) not invalid (the Texas decision).

In view of the reversal, the Federal Circuit vacated the Texas court’s related infringement judgment and damages award against Daiichi Sankyo (TYO: 4568) In a separate decision, the Federal Circuit also dismissed as moot Seagen’s appeal from the US 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).

This appeal was rendered moot by the Federal Circuit’s holding that the same claims were invalid in the appeal from the Texas decision.