In the recent case of Amgen Inc. v. Sanofi, Aventisub LLC, the Federal Circuit affirmed the district court’s invalidation of certain of Amgen’s antibody patent claims, concluding that the claims were not “enable[d]” under 35 U.S.C. § 112. This decision establishes that it is more difficult to satisfy the enablement requirement for antibody claims that use functional language to describe the antibody. (The court granted Amgen’s motion to extend the deadline for filing a petition for panel rehearing and/or rehearing en banc until April 14, 2021. See id., Order (March 8, 2021).)