Otsuka Pharmaceutical Co., Ltd. v. Sandoz, Inc. et al. (the “Defendants”)

Docket No. 2011-1126, -1127

May 7, 2012

Brief summary: Otsuka’s patent encompassing the schizophrenia drug Abilify® found not obvious because the skilled artisan would not have selected proposed lead compounds as a starting point in development.

Summary: The “Defendants” appealed from USDC NJ decision that Otsuka’s US 5,006,528 relating to the schizophrenia drug Abilify® (aripiprazole (7-{4-[4-(2,3- dichlorophenyl)-1-piperazinyl]-butoxy}-3,4- dihydrocarbostyril); a carbostyril derivative). The Defendants proposed three lead carbostyril derivative compounds in their obviousness arguments: the “unsubstitued butoxy”, 2,3-dichloro propoxy, and “OPC-4392” (the only compound tested in humans as an antipsychotic, although the others were at least suggested to be useful in treating CNS disorders). The DC determined, however, “that the asserted prior art did not teach one of ordinary skill to select” any of these as lead compounds. Instead, it concluded that “structurally dissimilar” compounds like clozapine or risperidone “would have been an attractive lead compound.” The Defendants argued that the DC “erred by assuming that ‘only the most obvious choice could serve as a lead” and that the secondary considerations did not render the claimed compound nonobvious. The FC agreed with the DC, however, citing Daiichi (FC 2010; prima facie obviousness under the third Graham factor generally turns on the structural similarities and differences between the claimed compound and the prior art compounds) and Altana (FC 2009; a lead compound is “a natural choice for further development efforts”), noting that “mere structural similarity…does not inform the lead compound selection” (Daiichi). And the second part of the inquiry is “whether the prior art would have supplied one of ordinary skill in the art with a reason or motivation to modify a lead compound to make the claimed compound with a reasonable expectation of success” (citing Takeda, FC 2007; Pfizer, FC 2007; and In re Dillon, FC 1990) which “may come from any number of sources and need not necessarily be explicit in the prior art” (Eisai, FC 2008; Aventis, FC 2007 (“expectation,’ in light of the totality of the prior art, that the new compound will have ‘similar properties’ to the old”). In this case, the panel concluded the DC’s reasoning was sound because “[a]t the relevant time, there were no carbostyril compounds that were marketed as antipsychotics or were publicly known to have potent antipsychotic activity with minimal side effects” and “[c]arbostyrils were thus not plausible lead compounds, except in retrospect”. Regarding the OPC-4392 arguments, the FC explained that Otsuka’s own development efforts (“short timeline”, “only ‘took a few months'”) could not “lead[] to a conclusion of obviousness; that is hindsight…[w]hat matters is the path that the person of ordinary skill in the art would have followed, as evidenced by the pertinent prior art” (citing 35 USC 103(a) and Life Techs. (FC 2000)). The FC also agreed that there was no obviousness-type double-patenting due to structural differences from the compounds of the asserted patent (“the prior art would not have provided a skilled artisan with a reason to make the necessary structural changes to the unsubstituted butoxy to yield aripiprazole.”)

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