On September 20, 2016, the U.S. Court of Appeals for the Federal Circuit issued an opinion affirming the summary judgement that Abbott’s U.S. Patent No. 5,344,915 (“the ’915 Patent”) was sufficiently supported by the written description of its priority application (“Priority App”) and thus entitled to the Priority App filing date. The ’915 Patent is directed to a protein, TBP-II, that binds to and neutralizes TNF-alpha. However, the Priority App discloses only a partial N-terminal sequence of the claimed protein (9 of 15 residues), along with other properties of the protein, including molecular weight, biological activity, and trypsin-degradation characteristics.

The Board of Patent Appeals and Interferences and the District Court

The issue in this case involves both timing and support for claims in a specification. Here, the Priority App was filed before an anticipating reference was published (“Engelmann”). Thus, if the ’915 Patent is entitled to the Priority App filing date, Engelmann is not prior art to the ’915 Patent. The Board initially found that the ’915 Patent was not entitled to the filing date of the Priority App, and thus, the claims were anticipated by Engelmann.

The District Court disagreed with the Board, finding that the Priority App inherently disclosed TBP-II, such that the ’915 Patent was entitled to the Priority App filing date, and Engelmann was not prior art (and thus could not anticipate the ’915 Patent claims). The case was remanded to the Board, which then found that the ’915 Patent was not anticipated.

The Federal Circuit

The Federal Circuit agreed with the District Court and the Board (after remand), explaining that inherent disclosure may be relied on when a specification describes an invention that has certain undisclosed yet inherent properties. Such a specification provides sufficient written description to support a later application that expressly recites these inherent properties. Here, the full N-terminal sequence was not expressly disclosed in the Priority App, but the full protein is claimed in the ’915 Patent.

The Priority App filing date is only effective if the later-claimed invention was sufficiently described in the original filing. This requires the Priority App to disclose the invention in a way that clearly demonstrates to those in the art that the inventor invented what is claimed and possessed the claimed subject matter at the date of filing. The Court noted that TPB-II is the only known protein with the same partial N-terminal sequence and the additional properties disclosed in the Priority App. Accordingly, the specification of the Priority App, as a whole, provides sufficient written description to inherently disclose TBP-II as-claimed in the ’915 Patent. Thus, the ’915 Patent is entitled to the filing date of the Priority App, rendering the Engelmann reference not prior art to the ’915 Patent.

Practical Considerations

The Federal Circuit relied on the robust disclosure of the Priority App in holding that the ’915 Patent was entitled to the earlier filing date. Specifically, the Court focused on additional properties of the protein that were recited in the Priority App. Thus, Applicants may find it advantageous to provide not only sequence/structural information, but also other known properties such as molecular weight, binding constants, biological activity, and degradation characteristics when drafting applications related to biomolecules. Here, the inventors knew of the closest prior art, TBP-I, and thus knew they must generate sufficient characterization data to distinguish the claimed TBP-II from the known TBP-I. However, reciting additional characteristics may become important if inherent disclosure is relied upon to claim any later-discovered properties. Moreover, the additional characteristics may also become critical for distinguishing prior art references disclosing similar sequence/structure information, even if the closest art is not known at the time of filing.