By Irena Royzman and Andrew Cohen (November 1, 2017, 12:11 PM EDT) -- On Oct. 5, the Federal Circuit issued a decision in Amgen Inc. v. Sanofi (No. 2017-1480), a closely watched case involving functional antibody claims, claims that define antibodies not by their sequence or structure but by their function, such as the ability to bind a biological target. The Federal Circuit held that although written description and enablement of such claims are assessed at the priority date, post-priority-date evidence is relevant to determining the breadth of the functional claims and whether antibodies representative of the claimed genus have been disclosed. The court also held that the disclosure of a new therapeutic target does not provide a written description of the antibodies that may bind and inhibit that target, even if it is routine to make such antibodies.[1] These holdings have important ramifications for the biotech industry....