On March 21, 2011, the Supreme Court denied a review of the Court of Appeals for the Federal Circuit’s (CAFC) decision in Daiichi Sankyo Company, Ltd. et al. v. Matrix Laboratories, LTD., Mylan Inc. et al. (Mylan). The case was decided in September, 2010.

In the Federal Circuit case, Mylan alleged that claim 13 of U.S. Patent No. 5,616,599, which covers olmesartan medoxomil, was invalid as obvious under 35 U.S.C. 103. Olmesartan medoxomil, an angiotensin receptor blocker, is the active ingredient in Benicar®, Benicar HCT®, and Azor®, which are used in the treatment of high blood pressure. The CAFC disagreed with Mylan’s arguments, and upheld the ‘599 patent as valid. In their analysis, the court relied on the “lead compound analysis,” first introduced in Yamanouchi Pharm. v. Danbury Pharmacal (CAFC 2000), which provides a two-step analysis for the determination of small-molecule obviousness: 1) determine whether one of skill in the art would select a particular compound(s) to serve as a starting point for chemical modification (a “lead compound”); 2) consider whether a chemist would have had some reason to modify the known compound in the particular manner necessary to achieve the new compound. The court held that none of the cited prior art compounds (e.g., example 6 of U.S. Patent 5,137,902) represented a lead that one of skill in the art would be motivated to modify; the lack of a lead notwithstanding, the court further held that there was no teaching in the art to make the molecular modifications necessary to arrive at olmesartan medoxomil.

Please click here to view diagram.

The Supreme Court has recently denied other petitions for writ of certiorari in pharmaceutical cases (see, e.g., Sanofi v. Apotex (CAFC 2008) (upholding claims to Plavix® as non-obvious) and Bayer v. Barr (CAFC 2009) (holding claims to a formulation of Yasmin® as obvious). The denial to review Daiichi v. Mylan, a case that relies heavily on the lead compound analysis, perhaps indicates that such an analysis does not constitute a “rigid preventative rule” that the Supreme Court warned against relying on in KSR v. Teleflex (2007).

You can view the Federal Circuit’s decision here.