Race to the Finish: Timing Battles in Parallel IPR and District Court Litigation

by Dennis Crouch

The new petition for certiorari filed by Liquidia raises some interesting questions about the ongoing race between inter partes review proceedings and district court litigation.  Liquidia Techs v. United Therapeutics Corp., 23-804 (US), on petition for writ of certiorari from United Therapeutics Corp. v. Liquidia Techs., Inc., 74 F.4th 1360 (Fed. Cir. 2023).

UTC won its infringement suit against Liquidia with a holding that its patent covering treprostinil administration by inhalation were valid and infringed. (US10716793).  While the appeal was pending, the PTAB sided against the patentee and found the claims unpatentable as obvious.  In the appeal, however, the Federal Circuit refused to give credence to the PTAB decision - finding that litigation was still "pending" and "non-final." The claims had not actually been cancelled yet - since the Director only issues the certificate confirming unpatentability after any appeal. Further, the Federal Circuit concluded that IPR decisions do not have issue-preclusive (collateral estoppel) effect until the decision is affirmed on appeal, or the parties waive their right to appeal. Citing XY, LLC v. Trans Ova Genetics, L.C., 890 F.3d 1282, 1294 (Fed. Cir. 2018).

Liquidia's petition argues that the PTAB's final-written decision should be given preclusive effect in parallel litigation even if an appeal is pending, just like would be done for a district court opinion.