A patent applicant’s misconduct during the prosecution of a patent can render the patent unenforceable under the doctrine of “inequitable conduct.” A recent U.S. Court of Appeals for the Federal Circuit decision, Regeneron Pharmaceuticals v. Merus, potentially extends that doctrine to encompass misconduct during patent-infringement litigation, rather than just during patent prosecution. See No. 2016-1346, 2017 WL 3184400 (Fed. Cir. July 27, 2017). We report here on the Regeneron case and other cases addressing whether litigation misconduct can render a patent unenforceable, and provide guidance for practitioners.
Inequitable Conduct
Inequitable conduct is an equitable defense to patent infringement, and a powerful one: a finding of inequitable conduct as to a single claim of a patent renders all claims of that patent unenforceable. Therasense v. Becton, Dickinson and Co., 649 F.3d 1276, 1289-90 (Fed. Cir. 2011). Inequitable conduct can also “spill over” to render unenforceable other patents within the same patent family. And it can lead to antitrust and unfair competition claims by competitors and consumers.
