In the United States, patent applicants and their counsel owe a duty of candor and good faith to the Patent Office. This duty is breached when the applicant or its counsel knowingly fails to disclose material prior art references prior to issuance. Where threshold levels of materiality of the reference and intent to conceal are found, a holding that inequitable conduct has occurred renders every claim in the offending patent unenforceable, a consequence that has often been characterized as ‘‘the ‘atomic bomb’ of patent law.’’

Prior to the landmark Therasense holding in 2011, courts had used a sliding scale to determine whether the requisite factual showing of materiality and intent had both been met, whereby a reduced showing of intent nonetheless could be salvaged by a strong showing of materiality, and vice versa.

Originally published in Pharmaceutical Law & Industry Report, 11 PLIR 482, 04/12/2013.