Maryland Bar Bulletin
Publications : Bar Bulletin : March 2010



Patent practitioners are no strangers to the duty of disclosure. But did you know that the Federal Circuit's recent decision in Therasense, Inc. v. Becton, Dickinson & Co., expanded the reach of the inequitable conduct doctrine around the globe?

In Therasense, the Federal Circuit affirmed the district court's ruling that one of the patents-at-issue was unenforceable due to applicants' failure to disclose statements made to a foreign patent office during an opposition proceeding, which refuted, or were inconsistent with, arguments made by the applicants before the United States Patent and Trademark Office (USPTO). The statements at issue involved representations of the teachings of applicants' own prior art and whether the claimed "test strip with an electrochemical sensor for testing whole blood without any membrane over the electrode," was taught by the prior art.

The prior art taught an electrochemical sensor for testing a whole blood sample, where "[o]ptionally, but preferably" a protective membrane is used with "live blood." Before the USPTO, the applicants argued that the "[o]ptionally, but preferably" language "should not be taken at face value." Rather, the applicants convinced the patent examiner to the contrary, submitting a declaration from an in-house scientist averring that the prior art taught that a membrane was required for the sensor. During the foreign opposition proceeding, however, the district court found that applicants had made directly contradictory statements. The same membranes in the prior art sensor that applicants argued as required before the USPTO became optional,but preferred, before the European Patent Office (EPO).

On appeal, the Federal Circuit stated that "[t]his is one of those rare cases in which a finding of inequitable conduct is appropriate," relying heavily on the district court's findings on materiality and intent.

The Scope of the Duty of Disclosure

Without question, the patent rules require each individual associated with the prosecution of a patent application to disclose information material to patentability, including information that "refutes, or is inconsistent with, a position the applicant takes in" opposing or forwarding arguments of patentability to the USPTO. The consequence of failing to disclose such information, as shown in Therasense, is the unenforceability of a patent obtained by the inequitable conduct.

To determine if inequitable conduct occurred during the procurement of a patent, a court will apply a balancing test based on the materiality of the information withheld and applicant's intent to deceive. In "balancing the levels of materiality and intent, ‘...a greater showing of one factor allow[s] a lesser showing of the other.'"


The Federal Circuit agreed with the district court that applicants' contradictory statements to the EPO were highly material and not clearly erroneous. In particular, the Federal Circuit noted that "[a]n applicant's earlier statements about prior art, especially one's own prior art, are material to the [US]PTO when those statements directly contradict the applicant's position regarding that prior art in the [US]PTO." Further, the court cautioned that in close cases, which Therasense was not considered to be, "the duty of disclosure requires that the material in question be submitted to the examiner rather than withheld."

The Federal Circuit also rejected the notion that the representations to the USPTO and the EPO were merely permissible attorney argument concerning the content of the prior art. The court distinguished cases where "‘applicant is free to advocate its interpretation of its claims and the teachings of the prior art,'" from the present case on the grounds that prior cases did not present "a situation in which contradictory arguments made in another forum were withheld from the [US]PTO."

Thus, if statements relevant to the patentability of a patent claim are made in a foreign jurisdiction, such statements will be considered as highly material if they directly contradict statements made to the USPTO.

Intent to Deceive

By finding that the failure to disclose the contradictory statements to the USPTO was highly material, a strong inference of applicants' intent to deceive did not need to be balanced by the court. However, the Federal Circuit noted that "‘[c]ases involving affidavits or declarations are held to a higher standard.'" As such, the applicants' declarant was under a "duty to avoid intentional deception in his declaration before the [US]PTO."

Practice Tips

Even though the Federal Circuit deemed Therasense a rare case, the decision nonetheless reinforces the importance of open and continuous dialog during prosecution between US and foreign counsel, particularly where management of a patent family is maintained in-house. Furthermore, best practices would be to provide US counsel with all arguments and declarations made to foreign patent offices, and vice versa, to prevent the exact situation in Therasense from happening. And as reemphasized in Therasense, when a decision to disclose or not to disclose statements might be close, the material in question must be submitted to the examiner rather than withheld.

Gaby L. Longsworth, Ph.D., Esq., is a director with the law firm of Sterne, Kessler, Goldstein & Fox P.L.L.C. She concentrates her practice in patent law. Jeremiah B. Frueauf, Esq., is an associate with the same firm, where he concentrates his practice in patent law.

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Publications : Bar Bulletin: March 2010

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