Billion Dollar Verdict Erased by Inadequate Description of Functional Claims

| Paige L. Cappelli


Before Moore, Prost, and O’Malley. Appeal from the United States District Court for the Central District of California.

Summary: Knowledge of a common general structure and the disclosure of two representative species is insufficient to support the written description of a functionally-claimed genus when the claimed function results from specific structures and the specification does not provide distinguishing characteristics for structures that achieve the claimed function and those that do not.

Juno sued Kite for patent infringement of claims to a genus of chimeric T cell receptors having a functionally-defined binding element and broadly defined binding targets. As part of its defense, Kite argued that the asserted claims were invalid for lack of written description because they covered “millions of billions” of possible candidates, only a fraction of which would satisfy the functional claim language, and the two embodiments disclosed in the specification were not representative. Juno, in turn, argued that potential candidates were well-known and possessed common structural features such that the two working examples were representative. Returning a verdict worth over $1.2 billion in damages, the jury found that Kite failed to prove that the asserted claims were invalid for lack of written description. Kite moved for judgment as a matter of law of inadequate written description, which the district court denied.

On appeal, the Federal Circuit reversed—holding that no reasonable jury could have found that the patent satisfied the written description requirement. Reiterating the standard from Ariad, the Federal Circuit emphasized that genus claims using functional language concerning binding “must demonstrate that the applicant has made a generic invention that achieves the claimed result and do so by showing that the applicant has invented species sufficient to support a claim to the functionally-defined genus.” Walking through the evidence, the Federal Circuit explained that even accepting that there were known candidates for both targets and binding elements, the specification lacked a disclosure that would distinguish the binding elements that would actually bind to a selected target from those that were incapable of binding. The Federal Circuit also noted that the common structure between the two examples and other candidates that Juno argued was insufficient here when a change to the amino acid sequence within the same general common structure would change the binding target and the specification failed to provide distinguishing characteristics for such structures. Thus, substantial evidence did not support the jury verdict, and the claims were invalid for want of written description.

Editor: Paul Stewart