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 claims. It also instructed the jury written description could be satisfied "by the disclosure of a newly-characterized antigen . . . if you find that the level of skill and knowledge in the art of antibodies at the time of filing was such that production of antibodies against such an antigen was conventional or routine." It then issued a permanent injunction.
First, the Federal Circuit reversed and remanded for a new trial on written description and enablement. It held post-priority-date evidence could be used to show the lack of sufficient representative examples or a structure-function correlation adequate to satisfy the written description requirement. It distinguished this from the improper use of post-priority-date evidence to "illuminate the state of the art on the priority date." It applied that reasoning to similarly hold post-priority-date evidence could be used to show undue experimentation for enablement purposes.
The Court then held that the district...