Amgen Inc. v. Sanofi

Amgen Inc. sued Sanofi and Regeneron for patent infringement, alleging that their PCSK9 inhibitor drug Praluent infringed Amgen’s patents covering monoclonal antibodies that bind to PCSK9 and block LDL receptor interaction. The patents claimed a broad genus of antibodies by function, but only disclosed 26 specific antibody amino acid sequences. Sanofi countered that the patents were invalid for lack of enablement under 35 U.S.C. §112(a), as they failed to teach how to make and use the full claimed class without excessive experimentation. The District of Delaware and the Federal Circuit agreed, holding the patents invalid. The U.S. Supreme Court granted certiorari and, on May 18, 2023, unanimously affirmed the invalidity ruling.

The Supreme Court issued a unanimous 9-0 decision affirming the Federal Circuit, holding that Amgen’s patents were invalid for failing to enable the broad functional claims, as they provided only a small number of examples and required substantial trial-and-error discovery.

Whether Amgen’s patents satisfied the statutory enablement requirement, considering that the functional genus claims potentially encompass millions of undisclosed antibodies, and whether a skilled artisan would need to engage in undue experimentation to practice the full scope of the invention.

The ruling significantly restricts the use of overly broad functional patent claims in biotechnology, forcing inventors to provide more detailed disclosures. It is expected to lower barriers for biosimilars, foster drug competition, and influence patent drafting strategies across the pharmaceutical industry, potentially affecting drug pricing and innovation incentives.