Addressing the doctrine of inherent disclosure, the US Court of Appeals for the Federal Circuit held that a protein can satisfy the written description requirement when the priority application discloses only a partial amino acid sequence. Yeda Research and Development v. Abbott GMBH & Co. KG, Case No. 15-1662 (Fed. Cir., Sept. 20, 2016) (Reyna, J).

Abbott is the owner of a patent that discloses and claims a protein called TBP-II with a particular 15 amino acid sequence at its N-terminus. The patent claimed priority to two applications that only disclosed a partial (9 out of 15) N-terminus amino acid sequence, a protocol for obtaining TBP-II from its biological source, and other properties of the protein. At issue was whether the patent was entitled to claim priority to the earlier applications. If not, it would be invalid as anticipated by an intervening prior art reference that described TBP-II. 

In a 1996 interference proceeding between Abbott’s patent and Yeda’s later-filed application, the Board of Patent Appeals and Interferences (now renamed the Patent Trial and Appeal Board) determined that Abbott’s patent was not entitled to claim priority to the earlier applications and was invalid. Abbott sought review of the Board’s decision in federal district court. The district court held that the priority application inherently disclosed the TBP-II protein and therefore provided adequate written description for the invention claimed in the patent.

On remand, the Board found that the priority application sufficiently disclosed TBP-II and that Abbott’s patent was entitled to the earlier priority date. Yeda again sought review in federal district court, which affirmed the Board’s decision. Yeda appealed the two district court decisions to the Federal Circuit, arguing that the district court applied the wrong legal standard for written description, that the prosecution history precluded Abbott from relying on inherent disclosure because the missing amino acids were material to patentability, and that the district court erred in affirming the Board’s finding of adequate written description. The Federal Circuit rejected each of these arguments.

Under the doctrine of inherent disclosure, when a specification describes an invention that has certain undisclosed yet inherent properties, that specification serves as adequate written description to support a subsequent patent application that explicitly recites the invention’s inherent properties. Applying this doctrine, the Federal Circuit held that “it is not necessary for an application to disclose a protein’s complete N-terminus sequence in order to provide an adequate written description of that protein.” In reaching this conclusion, Court relied on the fact that it was undisputed that the protein disclosed in the priority application was the same TBP-II protein claimed by Abbott’s patent. 

The Federal Circuit also found that the prosecution history of Abbott’s patent did not preclude Abbott from relying on the doctrine of inherent disclosure and did not demonstrate that the missing amino acids were material to patentability, because the partial amino acid sequence and biological properties disclosed in the priority application were sufficient to identify the TBP-II protein.