Addressing the slippery issue of inequitable conduct, the U.S. Court of Appeals for Federal Circuit upheld the district court’s ruling that two patents for cooking oil were unenforceable due to inequitable conduct. The patent applicant failed to disclose experimental data which contradicted the claimed oxidation properties of canola cooking oil. Cargill, Inc. v. Canbra Foods, Ltd., Case Nos. 06-1265, -1302 (Fed. Cir., Feb. 14, 2007) (Jordan, J., 3rd Cir., sitting by designation).

To hold a patent unenforceable due to inequitable conduct, “there must be clear and convincing evidence that the applicant (1) made an affirmative misrepresentation of material fact, failed to disclose material information, or submitted false material information and (2) intended to deceive the U.S. Patent and Trademark Office.”

The Court ruled that information is “material” if it meets the test of materiality either under new PTO Rule 56(b) (2006), or the “reasonable examiner” standard of Rule 56(a) (1991). Thus, the “reasonable examiner” materiality test remains the viable standard.

Under the “reasonable examiner” standard, “information is material where there is a substantial likelihood that a reasonable examiner would consider it important in deciding whether to allow the application to issue as a patent.” The Court held that a reasonable examiner “would certainly want to consider test data that is directly related to an important issue of patentability.”

The Court quotes Critikon, saying “intent may be inferred where a patent applicant knew, or should have known that withheld information would be material to the PTO’s consideration of the patent application.” Thus, the intent to deceive may be inferred if a patent applicant should have known, even if they did not actually know, that information was material to a reasonable examiner.

In this case, five of the rejections in the prosecution involved oil oxidation properties of the claimed invention, and the Court noted “[a]n applicant should know information is material when the examiner repeatedly raises an issue to which the information relates.” Thus, information that might not have been consider material by an applicant when the application was filed, might become material after an examiner makes a rejection.

Practice Note: Compliance with the “reasonable examiner” standard of materiality and the “should have known” standard of intent may, especially “the context of an extended prosecution involving many office actions, be burdensome—but must nevertheless be met. Many patent attorneys, being conservative and cautious, simply disclose as much information as possible when filing a patent application (when access to the inventor is most likely available). Ideally however, all those who have a role in the duty of disclosure (from the inventor, to in-house counsel, to outside counsel) should each consider, in the face of any particular office action, whether information already known (but not yet cited) is material in view of the patentability issues raised by the examiner.