OSI Pharm., Inc. v. Mylan Pharm., Inc.

To invalidate a patent on grounds of anticipation or obviousness, an alleged infringer must demonstrate that the patent is invalid with clear and convincing evidence.

Opinion (Robinson): OSI Pharmaceuticals (OSI) and Pfizer, Inc. owned patent nos. 5,747,498 (reissued as RE 41,065; “’065”) and 6,900,221 (’211), which were co-exclusively licensed to Genentech and used in the production of Tarceva, an anti-cancer drug. OSI, Pfizer, and Genentech sued Mylan Pharmaceuticals, Inc. (Mylan) for infringement of the ’065 and ’211 patents following its submission of an Abbreviated New Drug Application to the FDA, seeking permission to sell a drug that infringed those patents. Mylan conceded infringement, but argued that the patents were invalid as either anticipated or obvious in light of prior art. Mylan claimed that the prior art, which differed from the ’065 patent by a single molecule, showed that OSI’s substitution would have been obvious to a reasonably skilled medicinal chemist. The District Court, however, credited OSI’s evidence and expert witnesses, finding that the broad number of molecules that could have been substituted for the changed molecule, and the fact that the toxicity of the molecule used in the ’065 patent “taught away” from its use, precluded Mylan from establishing either obviousness or anticipation clearly and convincingly. The Court also rejected Mylan’s argument that the ’065 patent anticipated ’211, finding that the references at issue spoke of “thousands of compounds” that could be used in the treatment of various cancers. Similarly, the District Court found that the uncertainty surrounding the ultimate success of the chemical in ’221 prevented Mylan from establishing obviousness clearly and convincingly. Thus, the District Court entered judgment for OSI.