• Takeda Chem. Indus., Ltd. v. Alphapharm Pty., Ltd.
  • July 9, 2007
  • Law Firm: Nixon Peabody LLP - New York Office
  • On June 28, 2007, the Federal Circuit affirmed the district court’s judgment that U.S. Patent No. 4,687,777, which related to thiazolidinedione derivatives and their use to treat Type 2 diabetes, was not invalid for obviousness under 35 U.S.C. § 103. The Federal Circuit stated:

    “[S]tructural similarity between claimed and prior art subject matter, proved by combining references or otherwise, where the prior art gives reason or motivation to make the claimed compositions, creates a prima facie case of obviousness.” [A] prima facie case of obviousness also requires a showing of “adequate support in the prior art” for the change in structure. “Normally a prima facie case of obviousness is based upon structural similarity, i.e., an established structural relationship between a prior art compound and the claimed compound.” [C]lose or established “[s]tructural relationships may provide the requisite motivation or suggestion to modify known compounds to obtain new compounds.” A known compound may suggest its homolog, analog, or isomer because such compounds “often have similar properties and therefore chemists of ordinary skill would ordinarily contemplate making them to try to obtain compounds with improved properties.” [T]o find a prima facie case of unpatentability in such instances, a showing that the “prior art would have suggested making the specific molecular modifications necessary to achieve the claimed invention” was also required. That test for prima facie obviousness for chemical compounds is consistent with the legal principles enunciated in KSR.

    While the KSR Court rejected a rigid application of the teaching, suggestion, or motivation (“TSM”) test in an obviousness inquiry, the Court acknowledged the importance of identifying “a reason that would have prompted a person of ordinary skill in the relevant field to combine the elements in the way the claimed new invention does” in an obviousness determination. Moreover, the Court indicated that there is “no necessary inconsistency between the idea underlying the TSM test and the Graham analysis.” As long as the test is not applied as a “rigid and mandatory” formula, that test can provide “helpful insight” to an obviousness inquiry. Thus, 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. . . .

    Alphapharm failed to make that showing here. Alphapharm argues that the prior art would have led one of ordinary skill in the art to select compound b as a lead compound [by which] we understand Alphapharm to refer to a compound in the prior art that would be most promising to modify in order to improve upon its antidiabetic activity and obtain a compound with better activity. Upon selecting that compound for antidiabetic research, Alphapharm asserts that one of ordinary skill in the art would have made two obvious chemical changes: first, homologation, i.e., replacing the methyl group with an ethyl group, which would have resulted in a 6-ethyl compound; and second, “ring-walking,” or moving the ethyl substituent to another position on the ring, the 5-position, thereby leading to the discovery of pioglitazone. . . .

    Relying on KSR, Alphapharm argues that the claimed compounds would have been obvious because the prior art compound fell within “the objective reach of the claim,” and the evidence demonstrated that using the techniques of homologation and ring-walking would have been “obvious to try.” . . . We disagree. The KSR Court recognized that “[w]hen there is a design need or market pressure to solve a problem and there are a finite number of identified, predictable solutions, a person of ordinary skill has good reason to pursue the known options within his or her technical grasp.” In such circumstances, “the fact that a combination was obvious to try might show that it was obvious under § 103.” That is not the case here. Rather than identify predictable solutions for antidiabetic treatment, the prior art disclosed a broad selection of compounds any one of which could have been selected as a lead compound for further investigation. Significantly, the closest prior art compound (compound b, the 6-methyl) exhibited negative properties that would have directed one of ordinary skill in the art away from that compound. Thus, this case fails to present the type of situation contemplated by the Court when it stated that an invention may be deemed obvious if it was “obvious to try.” . . .

    Based on the record before us, we conclude that the district court’s fact-findings were not clearly erroneous and were supported by evidence in the record. [T]he court did not err in holding that Alphapharm failed to establish a prima facie case of obviousness.