REGENERON PHARMACEUTICALS, INC., v. MERUS N.V.,

REGENERON PHARMACEUTICALS, INC., v. MERUS N.V., Appeal No. 2016-1346 (Fed. Cir. July 27, 2017).  Before Prost, Newman, and Wallach.  Appealed from S.D.N.Y. (Judge Forrest).  (Inequitable Conduct)
Background:

In this case, Regeneron sued Merus for patent infringement.  Merus asserted a counterclaim of unenforceability due to inequitable conduct.  Merus argued that Regeneron withheld four references from the PTO during prosecution that were but-for material.  And, were withheld by Regeneron with the specific intent to deceive the PTO.  Regeneron argued that the references were not but-for material, but instead cumulative of references the PTO actually relied on during prosecution, and that Regeneron did not have any specific intent to deceive the PTO.

The district court bifurcated the trial based on the two elements of inequitable conduct (i.e., one for materiality, and another for intent).  The district court found that the withheld references were but-for material, but never held the scheduled second trial on specific intent.  Instead, the district court detailed Regeneron’s discovery misconduct and sanctioned Regeneron by drawing an adverse inference of specific intent to deceive the PTO.  The district court found that Regeneron failed to produce, inter alia, a number of documents on its privilege log relevant to topics in which privilege had been waived, such as its patent prosecutors’ mental impressions of the withheld references (waived by Regeneron when they filed trial declarations by the patent prosecutors).  Regeneron appealed.

Issues/Holdings:

Did the district court (i) err in finding the withheld references but-for material, and (ii) abuse its discretion by drawing an adverse inference of Regeneron’s specific intent to deceive the PTO?  (continue reading)

Summary by:  Bryan Hsu

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