The Federal Circuit recently issued a decision in the ongoing dispute in Kroy IP Holdings, LLC v. Groupon, Inc., addressing the collateral estoppel effect of Patent Trial and Appeal Board (PTAB) decisions on subsequent district court patent invalidity litigation.  The question presented was whether a PTAB finding of unpatentability in an inter partes review (IPR) proceeding should preclude relitigation of similar or patentably indistinct claims in district court, even though the standards of proof differ between the two forums.

On July 22, 2025, the Court of Appeals for the Federal Circuit concluded that the Patent Trial and Appeal Board’s (the “PTAB”) decision not to apply interference estoppel and, therefore, to institute an inter partes review (“IPR”), was unreviewable and affirmed the PTAB’s final written decision finding that the challenged claims were invalid for obviousness.

On May 7, 2025, the U.S. Court of Appeals for the Federal Circuit (“CAFC”) affirmed a decision by the U.S. District Court for the District of Delaware (“district court”) that found claims of two IOENGINE, LLC (“IOENGINE”) patents related to USB thumb drives—U.S. Patent Nos. 9,059,969 and 9,774,703 (collectively, “asserted patents”)—invalid as anticipated and rendered obvious by the prior art.  Ingenico Inc. v. IOENGINE, LLC, No. 2023-1367, ---F.4th---, 2025 WL 1318188, at *1 (Fed. Cir. May 7, 2025) (hereafter, “Ingenico”).  

On February 11, 2022, the Court of Appeals for the Federal Circuit (CAFC) affirmed a decision of the Patent Trial and Appeal Board (PTAB) terminating a petitioner’s participation in an inter partes review (IPR) based on the estoppel provision of 35 U.S.C § 315(e)(1).  Intuitive Surgical Inc. v. Ethicon LLC, No. 2020-1481 (Fed. Cir. Feb. 11, 2022).