The recent decision of the Fed. Cir. in Otsuka v. Sandoz, App. No. 2011-1126, -1127 (Fed. Cir. May 7, 2012) continues the courts admirable work in defining obviousness post-KSR. This case revisits the standards involved in making out a prima-facie case of structural obviousness. What is particularly interesting in this decision is the weight – or lack thereof – that the court gave to evidence of therapeutic utility of the closest prior art compound. In fact, the court applied the fairly obscure maxim of patent law articulated forty years ago In re Steminski, 444 F.2d 581 (CCPA 1971). John L. White, in Chemical Patent Practice, summarized the holding of Steminski as part of his discussion of the “Hass-Henze Doctrine”:
“The [CCPA] concluded that because the characteristics normally possessed by members of a homologous series [e.g., differing by only one methylene group] are principally the same, varying gradually from member to member [e.g., methyl, ethyl, propyl, butyl, etc], chemists knowing the properties of one member of a series would in general know what to expect in adjacent members so that a mere difference in degree is not the marked superiority which will ordinarily remove the unpatentability of adjacent homologs of old substances. Contra, where no use for the prior art compound is known [citing Steminski].”







