Written Description Support For Genus Claims In Mechanical Inventions: When Is A Single Species Enough?

The inquiry into the sufficiency of written description support turns on whether the disclosure of the application reasonably conveys to those skilled in the art that the inventor has possession of the claimed subject matter as of the filing date. See Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc). But when the claim is directed to a genus, is disclosure of a single species sufficient to support the claim? That issue was addressed by Synthes USA, LLC v. Spinal Kinetics, Inc., 734 F.3d 1332, 1338 (Fed. Cir. 2013).

Synthes sued Spinal Kinetics (SK) for infringement of claims directed to an intervertebral implant. The claims at issue in the litigation were added by amendment almost five years into the prosecution of the patent and after SK's accused infringing devices were on the market. Id. at 1341. In relevant part, the claims recite "a central part substantially located between the third and fourth plates, the central part including a flexible core and a fiber system, . . . wherein the fiber system . . . is at least partially received within the plurality of openings formed in the third and fourth plates so that the fiber system is joined to the third and fourth plates." Id. at 1336 (citation omitted). With these new claims, Synthes introduced the concept of "openings." The "opening" limitations were important because SK's devices thread their core fibers through circular slots within the cover plates to anchor the fiber system. The patent specification, on the other hand, disclosed only "grooves" on the perimeter of the plates. The parties agreed that "groove" is a type of "opening," but did not agree that it constitutes adequate disclosure to claim all openings located anywhere on the plates. Id. at 1342.

During litigation, the district court construed a number of terms, including "the third plate including a plurality of openings." As expected, SK argued that "plurality of openings" should be limited to "grooves on the circumference of the cover plate that radially penetrate into the lateral surface of the plate," as described in the specification. Id. at 1338. The court adopted a broader construction closer to Synthes's proposal: "the third plate including two or more openings to allow the fiber system to be joined or anchored to that plate." Id. at 1339 (citation omitted).

The jury concluded that the accused devices did not infringe the asserted claims, and that SK proved by clear and convincing...