Takeda v. Alphapharm, No. 2006-1329 (Fed. Cir. 2007)
In an opinion released today, the Federal Circuit affirmed the validity of Takeda's U.S. Patent No. 4,687,777, which covers pioglitazone HCl (among other compounds). Pioglitazone HCl is the active ingredient in ACTOS, Takeda's blockbuster drug for the treatment of type 2 diabetes. The decision is particularly important because the generic challenger, Alphapharm, had argued on appeal that the Supreme Court's recent decision in KSR v. Teleflex, as well as the Federal Circuit's recent decision in Pfizer v. Apotex, mandated reversal.
Alphapharm argued that pioglitazone HCl would have been prima facie obvious over a prior art compound, named "compound b," that is structurally similar to pioglitazone. According to the Federal Circuit, in chemical cases "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." Moreover, to prove prima facie obviousness based on structural similarity, "a showing that the prior art would have suggested making the specific molecular modifications necessary to achieve the claimed invention is also required."
The district court found that there was no motivation in the prior art to select compound b as a lead compound in the first place, and that the prior art taught away from its use as a lead compound. The Federal Circuit agreed with this finding, stating that it alone was a sufficient basis for concluding that Alphapharm had failed to establish a prima facie case of obviousness.
The Federal Circuit squarely addressed whether KSR affects its "structural obviousness" jurisprudence:
[The] 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.
The Federal Circuit concluded: "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."
In a separate decision today (made under Rule 36, without opinion), the Federal Circuit affirmed the district court's conclusion that the '777 patent is not unenforceable for inequitable conduct.