Federal Circuit Unravels Aventis' Tangled Web in Affirming Inequitable Conduct Finding

In 2011, an en banc panel of the Federal Circuit decided Therasense, Inc. v. Becton, Dickinson & Co., 649 F.3d 1276, 1290 (Fed. Cir. 2011) (en banc) and clarified that the standard for a patentee's “inequitable conduct,” rendering its patent unenforceable, was effectively the common law standard of fraud, thereby harking back to the prior, venerable “fraud on the patent office” characterization. At the time of the Therasense decision there was some question as to just how stringently the Federal Circuit would adhere to the nominal standards for common law fraud. Aventis Pharma S.A. v. Hospira, Inc., 675 F.3d 1324 (Fed. Cir. 2012), appears to answer that question for both patent prosecutors and litigators.