ottawa sign with aitken lee llc team

Apotex’ US Patent Unenforceable for Inequitable Conduct

In a relatively rare finding, the Court of Appeal for the Federal Circuit affirmed that Apotex’s U.S. Patent No. 6,767,556 is unenforceable due to inequitable conduct.

The 556 Patent is directed to a process for manufacturing moexipril magnesium tablets. Moexipril, an angiotensin converting enzyme inhibitor used to treat hypertension, was known to be prone to degradation and instability. In order to improve stability, the 556 Patent teaches a process of making moexipril tablets consisting primarily of moexipril magnesium obtained by reacting moexipril with an alkaline magnesium compound.

In 2012, Apotex sued UCB. for infringement of the 556 Patent based in part on the manufacture and sale of UNIVASC, a prior art moexipril tablet. In the context of that proceeding the U.S. District Court for the Southern District of Florida ruled that the 556 Patent is unenforceable due to inequitable conduct before the PTO.

The test for inequitable conduct consists of two prongs, materiality and intent to deceive. The first prong requires that the conduct is “but for material” to the issuance of the patent. Under the second prong, the “intent to deceive” must be the single most reasonable inference to be drawn from the applicant’s conduct.

The Court of Appeals affirmed the District Court’s finding that the inventor, Dr. Sherman, was responsible for the misconduct despite his attempts to disclaim knowledge and responsibility at trial. The evidence established that Dr. Sherman, the founder and chairman of Apotex, knew that UNIVASC was made using the process claimed in the 556 Patent but concealed this from the PTO and misrepresented material facts through counsel and an expert witness. The Court of Appeals agreed that the PTO only allowed the 556 Patent claims after the inventor’s misrepresentations and concluded that the 556 Patent would not have allowed but for this misconduct.

Under the second prong of the test, the Court  found that clear and convincing evidence established an intent to deceive the PTO. The evidence established that Dr. Sherman was aware he was attempting to patent the same process used to make UNIVASC, that some statements in the specification regarding prior art were at least misleadingly incomplete and that experiments described in the 556 Patent were never performed despite the specification being drafted entirely in the past-tense.

In affirming the finding of inequitable conduct, the Court  drew a line between an inventor’s personal belief and misrepresentations of material facts, stating the inventor “had no duty to disclose his own suspicions or beliefs regarding prior art. There is nothing wrong with advocating, in good faith, a reasonable interpretation of the teachings of the prior art.” The misconduct arose when the inventor “affirmatively and knowingly misrepresented material facts regarding the prior art.”

A copy of the decision can be found here.