Earlier today, the Supreme Court ruled that a good-faith belief regarding patent invalidity is no longer a defense to an induced infringement claim.Commil USA LLC v. Cisco Systems Inc., No. 13-896 (U.S. May 26, 2015).
Unlike direct infringement, which requires no knowledge of a patent or its infringement, indirect infringement - under either inducement or contributory infringement theories - requires knowledge of the patent and of its infringement by a customer or other third party. A good-faith belief of noninfringement negates the existence of such knowledge and remains a defense to indirect infringement. The Supreme Court in the Commil case, however, was unwilling to extend this reasoning to a good-faith belief in patent invalidity, because patents are presumed valid and an invalidity defense to indirect infringement undermines that presumption.
Prior art defenses will continue to carry substantial weight in inducement cases, although in the form of challenges to the validity of the patent itself. Likewise, IP due diligence and opinions, directed both to noninfringement and invalidity, remain critical in a business's decision regarding the launch or possible modification of a product, and as defenses to allegations of willful infringement.