PTO Reexamination Decision Is Binding In Concurrent Infringement Litigation

Many patents are involved in parallel proceedings — post-grant proceedings before the United States Patent and Trademark Office ("PTO") and infringement litigation in the courts.  What happens when the courts and the PTO do not reach the same conclusion concerning a patent's validity?  There is little guidance when there is a conflict in the judgments.  However, on July 2, 2013, the United States Court of Appeals for the Federal Circuit addressed the impact of a USPTO post-grant determination of patent invalidity on a damages award by a district court.  In Fresenius USA, Inc. v. Baxter Int'l., Inc., the Federal Circuit clarified what happens when the PTO cancels a claim in a reexamination even after there has been a court judgment.