In Therasense Inc. v. Becton, Dickinson and Co., Appeal No. 2008-1511(May 25, 2011), an en banc Federal Circuit issued a significant ruling on the elements necessary to establish an inequitable conduct defense. The stakes for a patent owner facing a charge of inequitable conduct are high: inequitable conduct renders the affected patent unenforceable and could support a finding that the case was exceptional, entitling the alleged infringer to attorneys fees. A party alleging inequitable conduct had to show that the patentee misrepresented or failed to disclose material information with an intent to deceive the Patent Office. The courts were then to engage in an equitable “balancing” of materiality and intent to determine whether the conduct justified finding the patents unenforceable.

While recent scholarship suggests that the defense was not particularly successful in cases that made their way to the Federal Circuit and that the Federal Circuit applied stricter standards as to the elements of the defense, the incentives to assert the defense were so great that patent litigators were alleging inequitable conduct as a matter of course. In fact, the defense of inequitable conduct was said to have been asserted in as many as 60 to 80 percent of patent infringement cases. Also, many believed that the standards for finding inequitable conduct elements had not been sufficiently articulated by the Federal Circuit.

In Therasense, a six-judge majority addressed those concerns by significantly tightening the standards to be used in assessing the materiality and intent elements. Most importantly, the majority held that in most circumstances the party asserting an inequitable conduct defense must establish that “but-for” the misrepresentation or omission, the patent would not have issued. Further, materiality and intent were held to be separate requirements and were no longer part of a sliding scale where a showing of greater materiality permitted a showing of lesser intent. The Federal Circuit did, however, recognize that in instances of egregious misconduct, a “but-for” showing would not be required.

The decision brings to a close an almost 30-year effort by the Federal Circuit to tighten up the standards for proving inequitable conduct which the Court had earlier described as “a plague” on the patent system. As a result, it was contributing to the massive citation of prior art to the PTO, which in turn contributed significantly to the backlog of patent applications. The use of the inequitable conduct defense was also said to have several other negative effects, such as the potential to destroy parts of patent portfolios/families, inhibit the possibility of settlement and cast a cloud over the reputations of inventors and patent prosecutors. Indeed, the Federal Circuit prefaced its holding by stating that it “now tightens the standards for finding both intent and materiality in order to redirect [the inequitable conduct] doctrine that has been overused to the detriment of the public.” Slip Op. at 24.

The Federal Circuit created an exception to the “but-for” materiality holding in the case of “affirmative egregious misconduct.” Id. at 29. One example of such egregious misconduct would be the filing of an unmistakably false affidavit. The Federal Circuit pointed out that the egregious misconduct exception provided a measure of flexibility to capture extraordinary circumstances.

In the Therasense case, the alleged misconduct had been the failure to disclose briefs that the patent applicant had submitted to the European Patent Office regarding the European counterpart of a related patent owned by the patent applicant. The District Court had found the patent unenforceable due to this failure to disclose. The Federal Circuit reversed and remanded and instructed the District Court to determine whether the PTO would not have granted the patent but for the failure to disclose the European Patent Office briefs. The Court also vacated the District Court finding of intent to deceive because it had decided this issue under the wrong standard. The District Court was instructed to determine whether there was clear and convincing evidence demonstrating that the patent applicant knew of the European Patent Office briefs, knew of their materiality and made the conscious decision not to disclose them in order to deceive the PTO.

The four judge dissent stressed that the “but-for” test of materiality departed from Federal Circuit precedent and was inconsistent with the PTO’s standard set forth in PTO Rule 56. The majority opinion’s response to the dissent was that the PTO’s Rule 56 standard was one of the major causes of the rampant use of the inequitable conduct defense.

The Patent and Trademark Office was quick to react to the decision. On May 26, 2011 it announced that it was “carefully studying the important en banc decision by the U.S. Court of Appeals for the Federal Circuit in the case of Therasense v. Becton, Dickinson to assess how it may impact agency practices and procedures.The agency also announced that it expects to soon issue guidance to applicants related to the prior art and information they must disclose to the Office in view of Therasense.” As the press release noted, the Therasense “decision resolves uncertainties in many aspects of how district courts must apply the inequitable conduct doctrine.”