Recently, the Federal Circuit reversed a jury decision upholding the validity of two Amgen patents directed to a large genus of antibodies that reduce LDL cholesterol. Amgen et al. v. Sanofi et al., No. 2017-1480.  Defendants argued that the patents failed to satisfy the written description and enablement requirements under 35 U.S.C. § 112.  The principal error on which the Federal Circuit reversed the decision was the district court’s exclusion of post-priority date evidence showing that defendants were required to perform substantial efforts in attempting to develop compounds covered by the asserted claims.

For a genus claim to meet the requirements of 35 U.S.C. § 112, a patent may disclose “a representative number of species falling within the scope of the genus[.]”  Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010).  The patents at issue provided three types of disclosures.  First, they explained that 3000 human monoclonal antibodies were screened to arrive at the claimed antibodies.  Second, they disclosed three-dimensional structures of two antibodies that fell within the genus.  Finally, they disclosed the amino acid sequences of twenty-two other antibodies that fell within the claims.  The research that supported the patents resulted in the development of Repatha™, which was not at issue in the case.

Contemporaneously, Defendants were researching similar antibodies, ultimately discovering Praluent®.  Amgen sued the Defendants based on their sale of this product.  The defendants stipulated to infringement, but argued that Amgen’s patents did not disclose a sufficient group of species to support the broader genus claims under 35 U.S.C. § 112.  To support this argument, Defendants sought to introduce evidence of their own development efforts that led to Praluent®, even though these occurred after the priority date.  Defendants argued this evidence showed that Amgen did not disclose a representative number of species within the genus claim as required by 35 U.S.C. §112.

The district court excluded this evidence, finding that it did not “illuminate[] the state of the art at the time of filing.”  The Federal Circuit disagreed, holding that evidence of future developments can be relevant to whether the patent disclosed a representative number of species so that the claims were enabled and adequately described as of the priority date.

Thus, proper framing of an enablement or written description defense may permit an accused infringer to rely upon post-priority-date evidence showing that the claimed subject matter was not adequately described or enabled.