Federal Circuit Casts Doubt On Antibodies Claimed By Epitope

In Amgen Inc. v. Sanofi, No. 2017-1480, the Federal Circuit reversed and remanded for a new trial because the district court (1) incorrectly excluded post-priority-date evidence regarding written description and enablement, and (2) erred in instructing the jury as to written description. It then vacated the permanent injunction.

Amgen owns two patents directed to anti-PCSK9 antibodies. The patents contain claims directed to the entire genus of antibodies that bind specific residues on PCSK9. In 2014, Amgen sued Sanofi and Regeneron ("Defendants") for infringement. They stipulated to infringement, but raised written description, enablement, and obviousness challenges.

The district court found the patents valid and infringed. At trial, it excluded Defendants' post-priority-date evidence purportedly showing that (1) the patents did not disclose a representative number of species, and (2) Amgen engaged in lengthy and potentially undue experimentation to enable its