Misrepresentation Requires Higher Level of Materiality than Mere Omission

The U.S. Court of Appeals for the Federal Circuit, on rehearing, vacated its prior holding of inequitable conduct and withdrew its earlier opinion in Purdue Pharma LP et al. v. Enro Pharmaceuticals Inc. et al., Case Nos. 04-1189, -1347, -1357 (Fed. Cir. Feb. 1, 2006) (Plager, S. J.).

Purdue filed an infringement suit against Endo alleging that Endo’s proposed generic versions of controlled release OxyContin pain relief medicine would infringe three Purdue patents. The district court found the patents were infringed but held the patents were unenforceable due to inequitable conduct. In its earlier opinion, (see IP Update vol. 8, No. 6, June 2005) the Federal Circuit upheld the district court’s judgment of inequitable conduct and, consequently, did not consider Endo’s cross-appeal on the infringement issue. Now, in its decision on rehearing, the Federal Circuit vacated the district court’s inequitable conduct judgment and affirmed the district court’s judgment that the patents were