In a recent decision out of the District of Massachusetts, Judge Stearns assessed Kaz’s inequitable conduct defense on summary judgment – and found it to come up short by a degree. The opinion is an important reminder that to make out an inequitable conduct defense, a litigant must make a strong showing as to both components of inequitable conduct: any withheld prior art references must be clearly material, and there must be clear intent by the patentee to deceive the patent office.

The case involves patents covering thermometers designed to measure internal body temperature at a particular spot over the temporal artery on a patient’s forehead. Kaz contended that Exergen had engaged in inequitable conduct by intentionally omitting several key prior art references during the prosecution of the patents-in-suit. There was no dispute that Exergen had been aware of the references during the prosecution of the patent in suit. And in Exergen’s view, the materiality of the references was so self-evident that the single most reasonable inference to be drawn from the evidence was that Exergen had intended to deceive the PTO.

To Judge Stearns, however, this line of argument was foreclosed by the Federal Circuit’s recent case law on the issue. To start, the Federal Circuit had rejected the argument that intent to deceive can be inferred solely based on non-disclosure of a reference that was known and material. And Dr. Pompei – the inventor of the patents at issue – had attested that did not submit the references because he, in good faith, believed that the references were not material. That attestation raised a competing reasonable inference – such that, even though deceptive intent was a possible inference, it was not the single most reasonable inference to be drawn. Because Kaz had not presented sufficient evidence to raise a genuine issue of material fact, its affirmative defense of inequitable conduct was dismissed on summary judgment.

Judge Stearns’ opinion highlights that the standard for inequitable conduct is quite high. Because the consequences for an inequitable conduct finding can be so sweeping, litigants attempting to assert it as a defense should bear in mind that courts will hold them to high standards of proof.

The case is Exergen Corp. v. Kaz USA, Inc., Civ. No. 1:13-cv-10628, in the District of Massachusetts. A copy of the opinion can be found here.