Last month, the USPTO issued a memorandum to its patent examining corps clarifying its guidance concerning the written description requirement for claims drawn to antibodies. In the memorandum, the USPTO adopts the Federal Circuit’s recent decision Amgen v. Sanofi, 872 F.3d 1367 (Fed. Cir. 2017).The Federal Circuit recently denied Amgen’s petition for rehearing and rehearing en banc in Amgen, confirming that Amgen is the law for written description for antibodies.

As the USPTO explains in the memorandum, the Federal Circuit’s decision in Amgen clarifies “the law of written description as it applies to antibodies.” In particular, as the USPTO points out, the “Federal Circuit explained in Amgen that when an antibody is claimed, 35 U.S.C. § 112(a) requires adequate written description of the antibody itself.” The USPTO also emphasizes that “the Amgen court expressly stated that the so-called ‘newly characterized antigen’ test, which had been based on an example in USPTO-issued training materials and was noted in dicta in several earlier Federal Circuit decisions, should not be used in determining whether there is adequate written description under 35 U.S.C. § 112(a) for a claim drawn to an antibody.”

The newly characterized antigen test allowed the description of a new antigen or target combined with routine and conventional methods of making antibodies to substitute for written description of the antibodies themselves, i.e., antibodies that may bind and inhibit that target. As the USPTO explains, the Federal Circuit rejected such an approach as contrary to the quid pro quo of the patent system: “Citing its decision in Ariad Pharm., Inc. v. Eli Lilly & Co., the court also stressed that the ‘newly characterized antigen’ test could not stand because it contradicted the quid pro quo of the patent system whereby one must describe an invention in order to obtain a patent.” In the case of claims that are drawn to antibodies, “35 U.S.C. § 112(a) requires adequate written description of the antibody itself.”

The USPTO also warns that examples in its 2008 written description training materials, which included an example that employed the newly characterized antigen test, are outdated: “The archived training materials are outdated and should not be relied upon as reflecting the current state of the law regarding 35 U.S.C. §§ 101 and 112.”

Finally, the memorandum instructs examiners to “continue to follow the guidance in the MPEP regarding written description . . . except insofar as MPEP 2163 indicates that disclosure of a fully characterized antigen may provide written descriptive support of an antibody to that antigen.” Other USPTO written description guidance also remains applicable—including a 2015 slide deck that discusses the other two most recent Federal Circuit decisions on written description for antibodies—except for its reference to the now-eliminated newly characterized antigen test in the written description training materials. In doing so, the memorandum excises the newly characterized antigen test from the USPTO’s instruction on antibodies while leaving all other written description guidance intact.

In promptly issuing guidance to the examining corps, the USPTO avoids having antibody claims that are contrary to Amgen and lack the required written description support to be allowed going forward.