On February 22, the U.S. Patent and Trademark Office issued a Clarification of Written Description Guidance for Claims Drawn to Antibodies and Status of 2008 Training Materials.  The update was prompted by the decision in Amgen v. Sanofi, 872 F.3d 1367 (Fed. Cir. 2017)

U.S. patent law requires that a patent specification contain a written description of the invention and enable the invention, i.e., details of how to make and use the invention. The written description requirement establishes that the applicant had possession of the invention at the time of filing.  The enablement requirement ensures that the inventor has adequately described, to a person of ordinary skill in the art, how to make and use the invention being claimed without undue experimentation.

The production of antibodies specific to an antigen was generally considered to be routine and thus, the USPTO in their MPEP followed the guidance set forth in Noelle v. Lederman (355 F.3d 1343 (CAFC 2004)), where it was held that an applicant satisfies the disclosure requirements for broad claims encompassing generically-described antibodies, provided that the applicant had sufficiently characterized a novel antigen e.g.  by its structure, formula, chemical name, or physical properties, or by depositing the protein in a public depository.

In Amgen v. Sanofi, one of the issues raised on appeal was the district court’s instructions to the jury.  Specifically, the district court instructed the jury, over Appellants’ objection, that written description can be satisfied “by the disclosure of a newly characterized antigen by its structure, formula, chemical name, or physical properties 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.” J.A. 1580 (Amgen, Inc. v. Sanofi, page 6), i.e. instructions based in part on the written description requirements set forth by the USPTO.

In setting forth its repudiation of the "newly characterized antigen" test, the Federal Circuit declared that the jury instruction provided at the district court level allowed the jury to “dispense with the required finding of a ‘written description of the invention.’” 35 U.S.C. § 112 (Amgen v. Sanofi at page 16).  The court concluded that the test “allows patentees to claim antibodies by describing something that is not the invention, i.e, the antigen. The test thus contradicts the statutory “quid pro quo” of the patent system where ‘one describes an invention, and, if the law’s other requirements are met, one obtains a patent.’” (Amgen v. Sanofi at 18, Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1345 (Fed. Cir. 2010) (en banc)).

The court referred to its discussion of the “newly characterized antigen” test in Centocor Ortho Biotech, Inc. v. Abbott Labs., 636 F.3d 1341 (Fed. Cir. 2011), stating that in Centocor, “[w]e questioned the propriety of the “newly characterized antigen” test and concluded that instead of “analogizing the antibody-antigen relationship to a ‘key in a lock,’” it was more apt to analogize it to a lock and “a ring with a million keys on it.” (Amgen v. Sanofi at 15 citing Centocor Ortho Biotech, Inc., 636 F.3d at 1352 and the testimony of Dr. Jochen Salfeld).

In the memorandum, the U.S. Patent and Trademark Office states that the examples provided in the 2008 Written Description Training Materials are “outdated and should not be relied upon as reflecting the current state of the law regarding 35 U.S.C. §§101 and 112.” The 2015-2016 training slides entitled “Antibody Decision and Their Compliance with the Written Description Requirement” may still be relied upon, except in the portions where they reference the 2008 training materials.  The U.S. Patent and Trademark Office also noted that MPEP 2163 should still be followed, except for where it indicates that disclosure of a fully characterized antigen may provide written descriptive support of an antibody to that antigen.