By Donald Zuhn --
Last week, the Federal Circuit affirmed a determination by the Board of Patent Appeals and Interferences that the claims of U.S. Application No. 10/041,958 would have been obvious in view of five prior art references.
The '958 application, filed by Appellants Saul Tzipori, Ramaswamy Balakrishnan, and Arthur Donohue-Rolfe (Tzipori), relates to antibodies that bind Shiga-like toxin II (SLT-II), which is secreted by some strains of Escherichia coli in the intestinal tracts of mammals. SLT-II-producing E. coli in the intestines of humans and pigs can create holes in the intestinal wall through which SLT-II can pass, causing a sometimes fatal disease, hemolytic uremic syndrome. The antibodies disclosed by Tzipori can be used to ameliorate the harmful effects of SLT-II.
During prosecution of the '958 application, Tzipori's claims were rejected by the examiner as obvious in view of five references: U.S. Patent No. 5,512,282 (Krivan); PCT Publication No. WO 90/07861 (Queen); Perera et al., J. Clin. Microbio. 26(10): 2127-31 (1988) (Perera); U.S. Patent No. 6,080,400 (Williams); and Danuta et al., Human Hybridomas and Monoclonal Antibodies 22-27 (Edgar G. Engleman et al., eds. 1985) (Engelman). The Board affirmed this rejection.
On appeal, Tzipori set forth a number of arguments for the nonobviousness of the claimed invention. Tzipori first argued that because the claims recite anti-SLT-II antibodies that specifically bind the alpha and beta subunits of SLT-II, the claims could be distinguished from Krivan (the primary reference cited against the '958 application), which does not disclose anti-SLT-II antibodies that bind a particular subunit of SLT-II. The Federal Circuit, however, noted that according to Tzipori, the only subunits of SLT-II are the alpha and beta subunits, and thus, "his implication that his claims are patentable because they are limited to the subunits 'responsible for the enteric and systemic disease in humans' rings hollow." The Court concluded that "Tzipori's claims are, as a whole, directed to all parts of SLT-II and no more specific than Krivan's disclosure on this point."
Tzipori next argued that his gnotobiotic pig model, which he used to determine effective doses of anti-SLT-II antibodies, was novel and rendered his claims patentable over the prior art. The Federal Circuit, however, noted that the gnotobiotic pig model did not figure into the into the claims at issue and therefore was "of little relevance to the obviousness inquiry."
Tzipori next argued that an important aspect of his studies was the use of a virulent strain of E. coli -- the 0157:H7 strain -- that infects and causes disease in humans. Again, the Federal Circuit countered by noting that "[Tzipori's] claims do not specify that the antibodies bind specifically to SLT-II from the 0157:H7 strain of E. coli, nor do they make clear how or whether the claimed antibodies differ from antibodies, such as those claimed by Krivan, which would be suitable for animal treatment."
Tzipori next argued that "there is no teaching in Krivan of the need in treating humans to make human or humanized antibodies to SLT II." The Federal Circuit, however, noted that "Tzipori has not proven that non-human antibodies are necessarily ineffective for human treatment."
While the CAFC conceded that Tzipori had established that Krivan did not disclose monoclonal or humanized antibodies to SLT-II, the Court noted that Queen disclosed a method of making humanized antibodies and Perara disclosed the manufacture of hybridomas that produce monoclonal antibodies. The Federal Circuit also reprimanded the Board for failing to offer facts or reasoning in support of its assertion that one of ordinary skill in the art would combine the references cited by the examiner, stating that:
Given the complexity of the technological issues and the combination of multiple references used to reject claim 26 [i.e., Tzipori's base claim], a more comprehensive explanation of the Board's reasoning would have facilitated review not only by better presenting the Board's reasoning to this court, but also by giving Tzipori a clearer idea why his claim was rejected.
Nevertheless, the Board's failure to better articulate the case for obviousness did not deter the CAFC from agreeing with the Board that the claims of the '958 application were indeed obvious.
In re Tzipori (Fed. Cir. 2008)
Nonprecedential disposition
Panel: Chief Judge Michel, Circuit Judge Friedman, and Chief District Judge Walker
Opinion by Chief Judge Michel
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