Inventions In Unpredictable Fields -- Not Always Unobvious

On Sept. 21, 2012, a three-judge panel of the Federal Circuit in In re Droge (2011-1600) held that the claims in U.S. patent application serial no. 10/082,772 (the '772 application"), directed to a method of recombining DNA in eukaryotic cells, were unpatentable for obviousness. The Federal Circuit affirmed the decision of the Board of Patent Appeals and Interferences, affirming the patent examiner's rejection for obviousness despite an expert opinion from the applicant that the prior art failed to provide an expectation of success in the claimed combination.

The declaration failed to specifically rebut the examiner's allegations and support from the scientific literature by using either scientific reasoning or by citation to contrary scientific literature or data. The field of biotechnology is viewed by the U.S. Patent and Trademark Office as generally unpredictable and biotechnology inventions are often found to be nonobvious because of this general unpredictability. In re Droge demonstrates that the prior art may establish enough predictability, which, if unrebutted by equally convincing evidence to the contrary, may be sufficient to sustain an obviousness rejection even in unpredictable fields.

The rejected claims in In re Droge are directed to a method for recombining (i.e., splicing) segments of DNA inside of a eukaryotic cell by application of particular DNA recombining enzymes (i.e., a recombinases) derived from the integrase family ("Int") of DNA recombinases. By way of background, a eukaryotic cell (e.g., a mammalian cell) contains nonsupercoiled chromosomal DNA within a specialized subcellular structure; the nucleus. This contrasts with prokaryotic cells (e.g., a bacterial cell), in which chromosomal DNA is negatively supercoiled and found free within the cytoplasm of the cell. The specific recombinases used by the '772 application, known as Int-h and Int-h/218, are mutated of the naturally-occurring Int recombinases.

The U.S. Patent Office rejected the claims as being obvious over two references, an issued U.S. Patent No. 6,143,530 to Crouzet and an article by Christ and Droge, who are two of the three inventors identified on the '772 patent application.

The patent examiner argued that Crouzet teaches recombining DNA in both eukaryotic and prokaryotic cells in the manner claimed except that the recombining enzyme was a naturally-occurring form of the Int recombinase. The examiner further argued that Christ and Droge describes...