Reminder: Estoppel May Not Preclude Prior-Art Systemsm PTAB Litigation Blog

Visit the PTAB Litigation Blog.

The estoppel statute precludes a defendant who has challenged a claim in an IPR reaching final written decision from later challenging that claim on any ground that it raised or reasonably could have raised during the IPR proceedings.  35 U.S.C. § 315(e)(2).  The boundaries of that rule were recently tested when a defendant asserted invalidity arguments before the district court in the Western District of Texas involving prior art systems in combination with prior art references that had been raised in the related IPR.  CliniComp Int’l, Inc. v. Athenahealth, Inc., No. A-18-CV-00425-LY, 2020 WL 7011768 (W.D. Tex. Oct. 28, 2020).

Read the full article at

Jones Day publications should not be construed as legal advice on any specific facts or circumstances. The contents are intended for general information purposes only and may not be quoted or referred to in any other publication or proceeding without the prior written consent of the Firm, to be given or withheld at our discretion. To request reprint permission for any of our publications, please use our “Contact Us” form, which can be found on our website at The mailing of this publication is not intended to create, and receipt of it does not constitute, an attorney-client relationship. The views set forth herein are the personal views of the authors and do not necessarily reflect those of the Firm.