In the April issue of our Life Sciences Newsletter last year we reported an imminent decision by the U.S. Federal Circuit about a much anticipated case which could have a significant impact on biotechnology patenting. On April 3rd, 2009, the United States Court of Appeal for the Federal Circuit (CAFC) issued a decision in In re Kubin affirming the Board’s obviousness decision of Kubin’s claims and, in the process, expanded the Court's obvious to try jurisprudence1.

Readers will remember that this case concerns a patent application for an isolated cDNA that encodes Natural Killer Cell Activation Inducing Ligand (NAIL), a protein also known as CD48. The Court had to lean towards the case after the Board of Patent Appeals and Interferences (BPAI) rejected the Kubin’s patent claims as invalid under both obviousness (§103) and unsupported by adequate written description (§112)2.

Regarding obviousness, two pieces of prior art were principally considered. The first document was a patent disclosing a receptor protein called “p38” and a monoclonal antibody specific for p38 (p38 was later found to be the same protein as NAIL)3. The patent further provides a theoretical example of how the monoclonal antibody might be used to clone p38, but it does not disclose the amino acid sequence of p38 recognized by the antibody nor the polynucleotide sequence that encodes p38. The second document was the well known Maniatis cloning manual (Sambrook et al.)4 which teaches conventional cloning techniques and protocols.

The CAFC affirmed the Board’s opinion on obviousness of the claimed cDNA in view of the two cited prior art documents, pointing out that the specification of the patent application itself explicitly stated that the nucleic acid molecule may be obtained “by standard biochemical methods (such as those outlined in Sambrook et al.)”. Therefore, the Court accepted the Board’s conclusions that a person skilled in the art would have been motivated by the prior art to make the DNA encoding the protein at issue and that such a person would have had a reasonable expectation of success given the teaching of how to use a monoclonal antibody specific to a protein to clone the corresponding gene.

The Court also had to deal with an earlier ruling which somewhat contradicted its current decision. In In re Duel5, the Federal Court held that “knowledge of a protein does not give one a conception of a particular DNA encoding it.” The Court had also stated that “obvious to try” was an inappropriate test for obviousness. The Court discarded Duel in view of the more recent Supreme Court KSR decision6 which partly overturned Duel saying that “the fact that a combination was obvious to try might show that it was obvious under §103” and that where a skilled artisan merely pursues “known options” from “a finite number of identified, predictable solutions”, obviousness under §103 arises.

In addition, the CAFC rejected the art-level distinction between allegedly predictable and unpredictable fields with respect to judging obviousness under KSR indicating that “[t]his Court also declines to cabin KSR to the “predictable arts” (as opposed to the “unpredictable art” of biotechnology)”.

Comment: This case makes it clear that any obviousness conclusion depends upon the level of enablement in the prior art. The CAFC may also have dismantled the belief that KSR applies only to the predictable arts thereby raising the bar not only for nucleic acid patent claims, but also for other kinds of biotech-related inventions in general.