Patenting Biotechnology Inventions Will Become More Challenging

The isolation and sequencing of a human gene that encodes a particular domain of a protein is the basis for many inventions in biotechnology. In a recent decision, however, the US Court of Appeals for the Federal Circuit held that claims to a specific DNA sequence were obvious and that it was "obvious to try" known methods to obtain the sequence.

Astrid R. Spain

In the case, In re Kubin, the invention focuses on DNA molecules encoding a protein known as the natural killer cell activation inducing ligand (NAIL). The patent specification discloses an amino acid sequence of a NAIL polypeptide, the isolation and sequencing of a polynucleotide that encodes a NAIL polypeptide, and the binding relationship between NAIL and a protein known as CD48.

The Board of Patent Appeals and Interferences rejected the claims over the combined prior art teachings of a patent and a laboratory manual. The prior art patent discloses a receptor protein called p38 that is the same protein as NAIL and further discloses, "[t]he DNA and protein sequences for the receptor p38 may be obtained by resort to conventional methodologies known to one of skill in the art." The Board concluded that one of ordinary skill in the art would have recognized the value of isolating NAIL cDNA and would have been motivated to apply conventional methodologies, such as those disclosed in the laboratory manual and used in the patent.

The Federal Circuit affirmed the Board's determination that the claims were unpatentable as obvious over the prior art. The Court held that the record supported the Board's factual determination that a person of ordinary skill in the art would have been motivated by the prior art to make a cDNA encoding the protein at issue given the prior art's teaching that the protein played a role in the immune response. The Court further sided with the Board that there would have been a reasonable expectation of success given the prior art's teaching of how to use a monoclonal antibody specific to a protein to clone the corresponding gene.

The Court rejected Kubin's argument that the prior art did not teach the claim's requirement that the "polypeptide binds CD48." The Federal Circuit effectively overruled, at least in part, its 1995 holding of In re Deuel, that claims to a genus of polynucleotide sequences coding for a known protein are not necessarily obvious. The Court concluded that "[i]nsofar as Deuel implies the obviousness inquiry cannot consider that the combination of the claim's constituent elements was 'obvious to try,' the Supreme Court in KSR unambiguously discredited that holding."

This decision, along with In re Gleave, rendered just a week earlier, represents an ongoing trend that makes patenting classic biotechnology inventions more challenging. In Gleave, the Court held that a comprehensive reference listing of every relevant sense oligonucleotide in a known nucleic acid sequence anticipates claims to specific antisense sequences. In the opinion's dictum, the Court appears to suggest that the patentability of claims to specific antisense sequences, without more, may be precluded for any known gene. More than ever, successful patenting strategies require careful planning and taking into account nuanced legal standards to ensure creation of a strong specification and prosecution record.

Astrid R. Spain is a partner at McDermott Will & Emery LLP, San Diego, CA, 858.720.3320, aspain@mwe.com