PTAB Terminates Instituted IPRs After Petitioner Becomes Estopped from Challenging the Claims

The PTAB terminated two instituted IPRs because the petitioner became estopped from challenging the claims as a result of final written decisions issuing in other IPRs.

The estoppel provisions of 35 U.S.C. § 315(e) attach to an IPR petitioner once a final written decision issues in the IPR. In addition to setting forth an estoppel provision that applies in district court, § 315(e) includes an estoppel provision for proceedings at the Patent Office. Specifically, § 315(e)(1) provides that once a final written decision is entered, the petitioner “may not request or maintain a proceeding before the Office with respect to that claim on any ground that the petitioner raised or reasonably could have raised during that inter partes review.” In Valve Corp. v. Ironburg Inventions Ltd., IPR2017-00136, Paper 43 (PTAB Jan. 25, 2018), the PTAB applied § 315(e)(1) and terminated two instituted IPRs because final written decisions had issued in two other IPRs, resulting in the petitioner being estopped from maintaining the pending IPR proceedings.


Petitioner Valve Corp. filed two IPR petitions challenging claim 20 of U.S. Patent No. 8,641,525 (“the ‘525 Patent”) and claims 1-4, 12, 15-18, and 20 of U.S. Patent 9,089,770 (“the ‘770 Patent”). The PTAB granted both petitions and ultimately issued two final written decisions holding all challenged claims of the ‘525 and ‘770 Patents unpatentable.

Before those two final written decisions issued, Valve Corp. filed two additional IPR petitions alleging that the same claims of the ‘525 and ‘770 Patents were anticipated in view of a prior art reference (“Wörn”). Wörn was not asserted as a prior art reference in either of the two earlier-filed IPR petitions.

The PTAB granted both of the later-filed IPR petitions on the Wörn grounds. After briefing had completed in the later-filed IPRs, but before the oral arguments took place, the PTAB issued issued final written decisions in the two earlier IPRs holding all of the challenged claims unpatentable.

In response to the final written decisions being issued, the patent owner Ironburg moved to terminate the later-filed IPRs under 35 U.S.C. § 315(e)(1). Specifically, Ironburg argued that upon issuance of the two final written decisions, Valve Corp. became estopped from maintaining the later-filed IPRs because Valve Corp. reasonably could have raised the pending IPR grounds based on Wörn in the two earlier IPRs.

The PTAB’s Termination Decision

The PTAB began its analysis by reviewing the legislative history of the America Invents Act. Based on the legislative history, the PTAB concluded that prior art that “could have been raised” includes “prior art which a skilled searched conducting a diligent search reasonably could have been expected to discover.”

To argue that a skilled searcher conducting a diligent search reasonably could have been expected to discover Wörn, Ironburg relied on a declaration from Bruce Rubinger, the Managing Director and founder of Global Prior Art. On the other hand, to argue that Wörn could not have been reasonably raised in the prior IPR petitions, Valve Corp. relied on declarations from an attorney representing it in the IPRs and another attorney who commissioned a prior art search for the first two IPR petitions.

After considering all of the parties’ evidence, the PTAB concluded that Ironburg sufficiently established that a skilled searcher conducting a diligent search reasonably could have been expected to discover Wörn. Wörn predated the critical dates of the ‘525 and ‘770 Patents and was classified in at least one class, sub-class of the United States Patent Classification (“USPC”) system where a skilled searcher would have been expected to search. Moreover, a skilled searcher would have discovered Wörn when performing either a manual search or a keyword search in the appropriate classes and sub-classes. Accordingly, the PTAB concluded that Valve Corp. reasonably could have raised the Wörn grounds in the earlier IPR petitions.

Because the PTAB had not yet made decisions on the merits for the IPRs involving Wörn, the PTAB determined that it was appropriate to to terminate both of the pending IPRs pursuant to 35 U.S.C. § 315(e)(1). Accordingly, the PTAB ordered the two pending IPRs terminated and canceled the oral argument that was to take place approximately one week later.