Addressing whether claims amended during prosecution to cover a competitor’s product were supported by the originally filed written description, the U.S. Court of Appeals for the Federal Circuit affirmed a jury verdict invalidating the patent finding that the applicant improperly broadened the patent claims during prosecution to claim a genus where the specification only disclosed a species of the genus.  Synthes USA, LLC v. Spinal Kinetics, Inc., Case Nos. 13-1047, 1059 (Fed. Cir., Oct. 29, 2013) (O’Malley, J.).

Plaintiff Synthes sued defendant Spinal Kinetics (SK) for infringement of a patent directed to a spinal implant medical device. The patent’s parent application, filed in 2003, disclosed and claimed grooves in plates of the implant that were used to anchor fibers in the implant to the plates. Five years after filing the application, the applicant amended the claims to replace the grooves with a plurality of openings, even though the disclosure did not describe openings generally. The parties agreed that grooves are a species of openings, but disagreed as to whether disclosing grooves is adequate to claim all openings.

During claim construction, SK argued the key claim term “plurality of openings” should be limited to grooves. However, the Court agreed with Synthes that a broader construction “two or more openings” applied. At trial, the jury found the patent invalid for lack of written description of “openings.”  After the district court denied Synthes motion for a judgment as a matter of law (JMOL), this appeal followed.  On review, the Federal Circuit examined the jury’s verdict to determine if it was supported by substantial evidence.

Notably, Synthes amended its claims to cover openings only after SK’s commercially successful product utilizing slots, and not grooves, hit the market. The Federal Circuit noted that it is acceptable to broaden claims during prosecution to cover a competitor’s product, but the broadened claims must be supported by the written description. Whether a claim has adequate written description is a question of fact, and the test for sufficiency of description is whether the disclosure reasonably conveys to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date.

The Federal Circuit analyzed the specification and noted that every embodiment only disclosed grooves and never disclosed openings or slots.  The Court also reviewed SK’s expert testimony, which highlighted significant biomechanical differences between using groove sand slots. Another SK witness, SK’s product developer, testified that it is not a simple substitution to go from grooves to slots. Indeed, SK’s original, failed prototypes used grooves, and it required months to develop the final design that utilized slots.

Synthes provided no evidence contrary to SK’s witnesses’ testimony, but only cross-examined the witnesses regarding whether deeper grooves would improve the design. Given the evidence the jury had to consider, the Court found that there was substantial evidence for the jury to rely on to find the claim invalid for lack of written description. The Court noted that written description is a factual question that is case-dependent and predictability in the art is a key fact. Here, SK’s evidence that its early prototypes utilizing grooves were failures, and that it took months of work to develop the successful slot design, could lead the jury to determine the use of slots was not predictable.