On May 9, 2023, in a significant reversal of a previous Patent Trial and Appeal Board (PTAB) decision, the Court of Appeals for the Federal Circuit (CAFC) ruled in favor of pharmaceutical giant Sanofi-Aventis Deutschland GmbH (“Sanofi”), upholding the validity of its patent (i.e., U.S. Patent No. RE47,614) for a drug delivery device and methods of using the same.

The dispute first arose when Mylan Pharmaceuticals Inc. (“Mylan”) initiated an inter partes review (IPR) of Sanofi’s ‘614 patent, alleging all 18 claims of Sanofi’s patent were obvious. In support of its petition, Mylan claimed that several references—namely, Burren (U.S. Patent Application No. 2007/0021718), Venezia (U.S. Patent No. 2,882,901), and de Gennes (U.S. Patent No. 4,144,957)—taught the ‘614 Patent to one skilled in the art. Despite Sanofi arguing that these references were unrelated to its patent, the PTAB concluded the ’614 patent was invalid using the “analogous art test,” which allows for the consideration of inventions from similar, but not identical, fields as a basis to claim a patent is invalid.

In ruling for Sanofi on appeal, however, the CAFC found that the applicability of the analogous art test—which serves the purpose of examining “whether a reference can be considered as prior art to the challenged patent in the first place”—was limited, as Mylan “adopted [a] problem statement derived from Burren and then worked backward to relate that problem to the ‘614 patent.” Furthermore, the CAFC reasoned that in evaluating “whether a reference is analogous, [the court] consistently held that a patent challenger must compare the reference to the challenged patent.” (emphasis added). As such, the CAFC agreed with Sanofi that the burden of proof to prove the claims’ unpatentability impermissibly shifted from Mylan to Sanofi, and ruled Mylan did not meet the requisite burden to connect de Gennes to the ‘614 patent such that a finding of invalidation would be proper. Accordingly, the CAFC reversed the PTAB’s decision to invalidate the ‘614 patent.

The case is Sanofi-Aventis Deutschland GmbH v. Mylan Pharmaceuticals Inc. (Case No. 21-1981) in the United States Court of Appeals for the Federal Circuit. The decision can be found at the following link: https://cafc.uscourts.gov/opinions-orders/21-1981.OPINION.5-9-2023_2123775.pdf