Proving and Avoiding Inequitable Conduct and Unclean Hands in Patent Prosecution and Litigation

Recording of a 90-minute premium CLE webinar with Q&A

Conducted on Thursday, July 30, 2020

Recorded event now available

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Course Materials

This CLE course will guide patent counsel on understanding the types of activity that may lead to a finding of inequitable conduct or unclean hands. The panel will also provide insights into practical tactics to avoid the risk of a court's ruling of inequitable conduct or unclean hands. The panel will also examine arguments that have worked to avoid a finding of inequitable conduct or unclean hands and those that haven't.


Some thought the 2011 en banc Therasense Federal Circuit decision sounded a death knell to the defense of inequitable conduct, but that was not the case. The defense is alive and continues to have broad applications, as recently seen in GS CleanTech Corp. v. Adkins Energy LLC (Fed. Cir. 2020) and Belcher Pharms., LLC v. Hospira, Inc. (D. Del. 2020).

The inequitable conduct defense traces its origins, at least indirectly, to a triad of "unclean hands" Supreme Court cases (Keystone Driller Co. v. General Excavator Co. (1933), Hazel-Atlas Glass Co. v. Hartford-Empire Co. (1944), and Precision Instrument Mfg. Co. v. Automotive Maint. Mach. Co. (1945)). These cases invoked the equitable doctrines of "unclean hands" and "equitable estoppel" to deny patent owners relief for infringement when the patents were obtained through fraud or bad faith. Several decades later, inequitable conduct cases share the stage with cases that resurrect the relatively ancient precedent to hold patents unenforceable for unclean hands (Gilead Scis. Inc. v. Merck & Co. Inc. (Fed. Cir. 2018)).

Supplemental examination provides a powerful tool for cleansing misconduct from a patent post facto. However, the statute's "fraud" exception may limit such cleansing effects of supplemental examination. In particular, if during a supplemental examination proceeding, the Director learns that a material fraud had been committed on the USPTO during patent prosecution, then the matter will be referred to the Attorney General for disciplinary proceedings against the patent attorney. The patent owner may also face criminal and antitrust claims under Section 257(f).

The webinar will address what, if any, will be the role of Supplemental Examination in cleaning up or purging Merck-type unclean hands, as well as purging more narrowly defined inequitable conduct. While the duty of disclosure ends with the issuance of the patent, it revives if a prosecution is reopened. That means the duty of disclosure applies in post-grant proceedings such as ex parte reexamination, reissue applications, AIA inter partes review, and AIA post-grant review. Defendants in litigation have requested amending counterclaims to add inequitable conduct based on an IPR proceeding. See, e.g., Jaguar v. Bentley, No. 2:18-cv-320. The rules relating to AIA post-grant proceedings expressly invoke a duty of candor and good faith and authorize the PTAB to apply sanctions against a party who does not meet that duty. To date, no such sanctions have been applied.

Listen as our authoritative panel of patent attorneys examines post-Therasense judicial decisions regarding inequitable conduct and unclean hands. The panel will offer examples of arguments that have worked to avoid a finding of inequitable conduct and unclean hands, and those that have not. The panel will outline practical suggestions to patent owners to avert inequitable conduct and/or unclean hands in patent prosecution/PTAB proceedings/Supplemental Examination and litigation.



  1. Post-Therasense Federal Circuit decisions
    1. Inequitable conduct
    2. Unclean hands
  2. Exemplary post-Therasense judicial rulings finding no inequitable conduct
    1. PTAB decisions imposing sanctions
    2. AIA's answer to possible inequitable conduct issues
    3. Supplemental examination: pre-litigation "car wash"?
    4. AIA reissue
    5. Do these corrective actions apply to unclean hands?
  3. Best practices
    1. Avoiding inequitable conduct and unclean hands
    2. How, if at all, can inequitable conduct and unclean hands be purged?


The panel will review these and other key issues:

  • What are the most common assertions defendants make when raising the inequitable conduct and unclean hands defenses?
  • What are best practices prosecutors and litigators should employ to avoid and/or defend against inequitable conduct or unclean hands allegations?
  • What guidance do post-Therasense decisions provide on the treatment of inequitable conduct?
  • What guidance do post-Therasense decisions provide on the reception to unclean hands defenses?
  • How will Supplemental Examination affect both unclean hands and inequitable conduct?


Browning, Paul
Paul W. Browning, Ph.D.

Finnegan Henderson Farabow Garrett & Dunner

Dr. Browning focuses on patent litigation and appeals. He has led teams as first chair at trial, at Markman...  |  Read More

Irving, Thomas
Thomas L. Irving

Finnegan Henderson Farabow Garrett & Dunner

Mr. Irving has 35 years of experience in the field of IP law. His practice includes due diligence, patent prosecution,...  |  Read More

MacAlpine, Jill
Jill K. MacAlpine, Ph.D.

Finnegan Henderson Farabow Garrett & Dunner

Dr. MacAlpine practices patent procurement, due diligence investigations, opinion work, and client counseling,...  |  Read More

Murphy, Amanda
Amanda K. Murphy, Ph.D.

Finnegan Henderson Farabow Garrett & Dunner

Dr. Murphy focuses her practice on client counseling and patent prosecution for a range of clients. She prepares new...  |  Read More

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