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 court also erred in instructing the jury on written description because “disclosing an antigen does not satisfy the written description requirement for a claim to an antibody.” It acknowledged earlier precedent implying an exception from the written description requirement for claims to an antibody binding a “newly characterized antigen,” but suggested that the “newly characterized antigen” test was mere dictum with “extremely limited” precedential value. The Court also noted that the district court’s instruction improperly conflated written description and enablement by allowing the jury to find “the claim adequately described merely because the antibody could easily be produced (and, implicitly, used as an antibody).”

The Court last affirmed the district court’s grant of JMOL of nonobviousness, noting the Dynamic Drinkware test for prior art under 35 U.S.C. § 102(e) applies not only to issued patents, but also to published applications. It noted Defendants proffered no evidence showing the district court erred in excluding their references as improper prior art.

In light of the above, the Federal Circuit vacated the permanent injunction and noted, in dictum, that the district court erred in (1) granting an injunction despite finding that the injunction would disserve the public interest, and (2) elevating the harm of removing a helpful drug from the market in its public interest analysis.