Federal Circuit Affirms Specific Intent To Deceive Based On Discovery Misconduct

In Regeneron Pharmaceuticals, Inc. v. Merus N.V., No. 2016-1346 (Fed. Cir. July 27, 2017), the Federal Circuit affirmed the district court's decision that the claims of U.S. Patent No. 8,502,018 were unenforceable due to Regeneron's inequitable conduct during prosecution.

The parties agreed that there were four references known to Regeneron during prosecution that were not cited to the Patent and Trademark Office (PTO). Regeneron, however, argued that these references were neither material nor were withheld with specific intent to deceive the PTO.

After a bench trial, the Southern District of New York determined that these references were material. In addition, the court drew an adverse inference of specific intent to deceive based on Regeneron's "widespread" discovery misconduct during the litigation. The Federal Circuit upheld the finding of "but-for" materiality for all four references based on the broadest reasonable interpretation of the claims and, based