Collateral Estoppel Does Not Attach To PTAB Invalidity Determination Pending Appeal

Recently, in Sanofi-Aventis v. Mylan, 2:17-cv-09105-SRC-CLW, Judge Stanley Chesler of the United States District Court, District of New Jersey, denied a motion by defendant Mylan for summary judgment of invalidity of asserted patent claims that were found to be obvious by the Patent Trial and Appeal Board ("PTAB").  With the appeal of those decisions pending, Judge Chesler reasoned that the difference in the burdens of proof applicable at the PTAB and in instant case barred the application of issue preclusion under Supreme Court guidance in B&B Hardware, Inc. v. Hargis Indus., 135 S. Ct. 1293, 1303 (2015).

The case arose on October 24, 2017, when Sanofi-Aventis U.S. LLC, Sanofi-Aventis Deutschland GmbH, and Sanofi Winthrop Industrie (collectively, "Sanofi"), filed suit for patent infringement against Mylan N.V., Mylan GmbH, Mylan Inc., and Mylan Pharmaceuticals Inc. (collectively, "Mylan"), after Mylan filed a New Drug Application with the United States Food and