On December 5, 2014, the Supreme Court granted certiorari in Commil USA, LLC, v. Cisco Systems, Inc., to decide whether a defendant’s good-faith belief that a patent is invalid is a defense to induced infringement.

Previously, a divided panel of the Federal Circuit held that a Texas district court should have allowed evidence that Cisco believed in good faith Commil’s patent was invalid.  At trial, Cisco was not permitted to present such evidence to rebut Commil’s claims of induced infringement.  The district court relied on Federal Circuit precedent, DSU Medical Corp. v JMS Co., which addressed a good-faith belief of non-infringement, not a good-faith belief of invalidity, as a defense.

Reversing the district court, the Federal Circuit reasoned that, because one necessarily cannot infringe an invalid patent, no principled distinction exists between a good-faith belief of non-infringement and a good-faith belief of invalidity.  Accordingly, the court held that evidence of a good-faith belief of invalidity is evidence that “should be considered by the fact-finder in determining whether an accused party knew that the induced acts constitute patent infringement.”  In dissent, Judge Newman argued that a good-faith belief of invalidity cannot be a defense to induced infringement of a patent that is actually valid and infringed.

For now, the Federal Circuit’s decision provides accused infringers with two means of defending against induced infringement claims: good-faith belief of non-infringement and good-faith belief of invalidity.  Considering the recent patent cases the Supreme Court has reviewed, it is uncertain whether both defenses will persist.