Answer ... Patent applicants and individuals associated with the filing and prosecution of an application have a duty of candour and good faith to the US Patent and Trademark Office (USPTO) (37 CFR § 1.56(a)). Breaching this duty of candour and good faith may constitute inequitable conduct that can render all claims of a patent unenforceable. Furthermore, subsequent patents – including continuations, divisionals or continuation-in-parts – that rely on the unenforceable patent may also be rendered unenforceable.

Persons having a duty of candour and good faith include:

• each inventor named in the application;
• each attorney or agent who prepares or prosecutes the application; and
• every other person who is substantively involved in the preparation or prosecution of the application and who is associated with the inventor, the applicant, an assignee or anyone to whom there is an obligation to assign the application (37 CFR § 1.56(c)).

Answer ... A breach of the duty of candour and good faith to the USPTO occurs when the applicant or its representative makes an affirmative misrepresentation of a material fact or omits material information, such as failing to disclose a material prior art reference or submitting false material information, with an intent to deceive the USPTO (Therasense, Inc v Becton, Dickinson and Co, 649 F 3d 1276, 1287 (Fed Cir 2011)). Proving inequitable conduct requires showing “intent” and “materiality” elements separately by clear and convincing evidence (id). A court should not use a “sliding scale” approach, meaning that a strong showing of materiality cannot overcome a weak showing of intent, or vice versa, to find inequitable conduct (id at 1290). To the contrary, “to meet the clear and convincing evidence standard, the specific intent must be single most reasonable inference able to be drawn from the evidence” (id (internal quotations omitted)). “When the two elements are satisfied, the court then weighs equities to determine whether rendering the entire patent unenforceable is warranted under the circumstances” (id).

A clear and convincing showing of an intent to deceive the USPTO requires that “the applicant made a deliberate decision to withhold a known material reference” (id at 1290). An undisclosed reference is material if the USPTO “would not have allowed a claim if it had been aware of the undisclosed prior art” (id at 1291). In determining a reference’s materiality, the court applies a preponderance of evidence standard and gives the patent claims their broadest reasonable construction (id at 1291-92).

Answer ... The duty of candour requires an applicant and anyone associated with the preparation and prosecution of an application (see question 5.1) to “disclose to the Office all information known to that individual to be material to patentability” (37 CFR § 1.56(a)). This duty “exists with respect to each pending claim until the claim is cancelled or withdrawn from consideration, or the application becomes abandoned” (id).