Jepson Claim Preamble Requires Written Description Support for Conventional Aspects of the Invention

Written by:Isabella C. Pestana and Justin J. Gillett

IN RE: XENCOR, INC.

Before Hughes, Stark, and Schroeder (sitting by designation).  Appeal from the U.S. Patent and Trademark Office, Patent Trial and Appeal Board.

Summary: To provide adequate written description for a Jepson claim, the applicant must establish that what is claimed to be well known in the prior art is, in fact, well known in the prior art.

Xencor filed a U.S. patent application with a Jepson claim and a method claim.  Both claims had preambles that recited “treating a patient by administering an anti-C5 antibody.”  The patent examiner rejected both claims for lack of written description.  After a series of appeals within the U.S. Patent Office and the Federal Circuit, the Appeals Review Panel (“ARP”) of the Patent Trial and Appeal Board affirmed the examiner’s rejection.  Xencor appealed the ARP’s decision to the Federal Circuit.

The Federal Circuit affirmed.  It noted a Jepson claim uses the preamble to recite elements or steps of the claimed invention that are conventional or known.  Xencor had agued those conventional or known aspects do not require written description support.  The Federal Circuit rejected that argument and noted adequate written description for a Jepson claim requires the applicant to establish that what is claimed to be well known in the prior art is, in fact, well known in the prior art.  The court found substantial evidence supported the ARP’s finding that Xencor did not do so for the “anti-C5 antibody” claimed in the preamble of its Jepson claim.  For Xencor’s method claim, the Federal Circuit affirmed that the preamble term “treating a patient” limited the claim and that Xencor’s patent application lacked written description for that term.

Editor: Sean Murray