Federal Circuit Affirms-in-Part and Vacates-in-Part PTAB Unpatentability Findings Based on Claim Construction

In Bayer Pharma Aktiengesellschaft v. Mylan Pharmaceuticals Inc., No. 23-2434 (Fed. Cir. Sept. 23, 2025), the Federal Circuit affirmed the PTAB’s judgment holding claims 1-4 of U.S. Patent No. 10,828,310 unpatentable and vacated and remanded the judgment holding claims 5-8 unpatentable.

Claims 1-4 recite, among other things, methods of administering rivaroxaban and aspirin in amounts “clinically proven effective” at reducing the risk of certain conditions. The claims also specified amounts of rivaroxaban and aspirin to be administered daily. Bayer argued that “clinically proven effective” is limiting and requires clinical proof of efficacy as shown, for example, by clinical trial results, but the Board concluded that the phrase was non-limiting and, in the alternative, inherently anticipated.

For claims 5-8, Bayer argued that the claim phrase requiring administration of “a first product comprising rivaroxaban and aspirin” required that the “first product” be a single dosage form that includes both rivaroxaban and aspirin. The Board, however, determined that the claim phrase was not limited to a single dosage form but could be multiple dosage forms administered simultaneously or sequentially.

On appeal, the Federal Circuit affirmed the Board’s construction of “clinically proven effective” in claims 1-4. The court first noted concerns with clawing back from the public domain otherwise anticipated methods of treatment merely by adding a limitation that the method later succeeded in clinical trials. The court then held that “clinically proven effective” could not make the challenged claims patentable because it lacks a “new and unobvious functional relationship” with the other parts of the claims, which the Board determined to be unpatentable. The court further held that because the claims already specify the exact dosages of rivaroxaban and aspirin to be administered to a patient, the additional limitation does nothing to further define the dosages that are administered. The court therefore affirmed the Board’s unpatentability determination for claims 1-4.

Finally, the Federal Circuit disagreed with the Board’s construction of “first product” in claims 5-8 and held that the claims require a single dosage form that includes both rivaroxaban and aspirin. The court found that interpreting “first product” to allow for separate dosage forms would render “a first product comprising” meaningless. As a result, the court vacated the Board’s unpatentability determination for claims 5-8 and remanded for further consideration of the obviousness arguments under the correct construction.