Federal Circuit partly grants Bayer second chance in defending rivaroxaban patent invalidation campaign

Context: In February 2022, Mylan Pharmaceuticals, Teva Pharmaceuticals, and Invagen Pharmaceuticals filed parallel petitions for inter partes review (IPR) of German pharma giant Bayer’s U.S. Patent No. 10,828,310 (“Reducing the risk of cardiovascular events”) in the United States Patent and Trademark Office’s (USPTO) Patent Trial and Appeal Board (PTAB). The patent is related to methods for reducing the risk of cardiovascular events in patients with coronary artery disease and/or peripheral artery disease by administering rivaroxaban and aspirin. An IPR was granted by the board six months later (August 9, 2022 IPR decision), and, in July 2023, the PTAB held the patent’s claims unpatentable as anticipated and obvious. Bayer filed an appeal with the Federal Circuit.

What’s new: The Federal Circuit yesterday affirmed the USPTO PTAB’s decision finding claims 1-4 of the patent unpatentable, vacated the findings of unpatentability for claims 5-8, and remanded the judgment for further proceedings (September 23, 2025 Federal Circuit decision).

Direct impact: While the first four claims of the Bayer patent will not be revived, the latter four could be, depending on what the PTAB decides on remand.

Wider ramifications: Most notably, the court’s precedential decision does not recognize “clinically proven effective” as a claim limitation that makes the difference between something being patentable or not. While the Federal Circuit agrees with the PTAB that “clinically proven effective” does not make something already-disclosed patentable, it notes that if, in the meantime, a clinical trial has been conducted, there can be an exception. The Federal Circuit’s only concern, however, is that a patentee could then receive new patent protection without inventing a new substance or identifying a new dosage for a given purpose.