Inequitable Conduct and Supplemental Exam in Patent Prosecution Post-Lindis

A recent decision, Lindis Biotech v. Amgen, by the U.S. District Court for the District of Delaware on Aug. 20, 2025, reminds patent counsel that parties involved in the patent application process have a duty to disclose material information to the USPTO. The court held that Lindis Biotech withheld material information with the specific intent to mislead the USPTO, which supported the finding of inequitable conduct. This ultimately resulted in the patent being unenforceable.

To prove inequitable conduct under Therasense (Fed. Cir. 2011), a party must demonstrate how the accused party either withheld material information from the USPTO with specific intent to deceive or committed affirmative egregious misconduct. As the court held that Amgen did not prove affirmative egregious misconduct, it is still debatable whether specific intent to deceive the USPTO is required in the presence of affirmative egregious misconduct.

Supplemental examinations, which came into effect in 2012 under the AIA, provide a path for possibly cleansing misconduct (a car wash) from a patent after issuance. However, the Supplemental Examination statute's (1) "material fraud" exception and (2) its rule of construction that nothing in the Supplemental Exam statute (35 U.S.C. §257) precludes the imposition of sanctions based on criminal or antitrust law, such as Clayton Act Section 1 and Section 5 of the Federal Trade Commission Act, may limit such cleansing effects of supplemental examination. There are thus possible limitations, although to be sure the MPEP 2800 states that instances of material fraud and antitrust violations are anticipated to be rare.  

A request for supplemental exam is apparently not available if certain litigation allegations dealing with the issues pled or set forth with particularity exist before the date of a supplemental examination request to consider, reconsider, or correct information forming the basis for the allegation.

Also, in a patent enforcement action, no car wash effect apparently applies to any defense raised in the action that is based upon information that was considered, reconsidered, or corrected pursuant to a supplemental examination request unless the supplemental examination request, and any reexamination ordered pursuant to the request, are concluded before the date on which the patent enforcement action is brought.

Listen as our panel of experienced patent attorneys examines judicial decisions regarding inequitable conduct as examples of the type of activity that can lead to a finding of inequitable conduct and examples of arguments that have worked to avoid a finding of inequitable conduct. The panel will offer practical suggestions to patent owners for trying to avoid committing inequitable conduct in patent prosecution. 

I.  Decision and court guidance

A. Inequitable conduct findings

B. No finding of inequitable conduct

II. Availability of post-issuance supplemental examination to cleanse a patent

III. Best practices

A. Avoiding inequitable conduct

B. Proving inequitable conduct

The panel will review these and other key issues:

• What are best practices that prosecutors should pursue in patent drafting and prosecution to minimize the success of inequitable conduct allegations?
• What are best practices that litigators should employ when pursuing and defending inequitable conduct allegations?
• What guidance do post-Therasense decisions provide on how inequitable conduct will be treated?
• How can supplemental examination affect inequitable conduct?