Evidence Showed that Claimed Compound was Not Obvious To Try

Takeda Chemical Industries, Ltd. v. Alphapharm Pty., Ltd., [06-1329] (June 28, 2007) [LOURIE, Bryson, Dyk] The Federal Circuit affirmed the district court's determination that the claims of U.S. Patent No. 4,687,777 were not invalid for obviousness.
BRIEF: A prima facie case of obviousness of a chemical compound is made by showing a similarity in structure and that the prior art would have suggested making the specific molecular modifications necessary to achieve the claimed invention. The Federal Circuit said that in cases involving new chemical compounds, it remains necessary to identify some reason that would have led a chemist to modify a known compound in a particular manner to establish prima facie obviousness of a new claimed compound. The Federal Circuit agreed with the district court that the starting compound proposed by Alphapharm would not have been selected by one of ordinary skill in the art, because a person of ordinary skill in the art would avoid the known undesirable side effects. The Federal Circuit said that this case fails to present the type of situation contemplated by the Supreme Court in KSR when its stated that an invention may be deemed obvious if its was "obvious to try" because the evidence showed that it was not obvious to try. Even if the starting compound was obvious, the Federal Circuit agreed that defendant did not show that the modifications to the starting compound to make the claimed compound were obvious. First, at the time, homologation and ring-walking were not obvious at the time, second, there was no reason to focus only on the methyl groups, and finally, there was not indication that modification would affect toxicity or otherwise effect beneficial changes.