Federal Circuit Resolves Circuit Split on Scope of IPR Estoppel

As part of the 2012 America Invents Act, statutory estoppel was included to balance the interests of patent owners and patent challengers following an inter partes review (“IPR”).  Estoppel prevents an IPR petitioner from later asserting in court that a claim “is invalid on any ground that the petitioner raised or reasonably could have raised” during the IPR.  35 U.S.C. § 315(e)(2).  As applied, estoppel prevents petitioners from later relying in district court or in ITC proceedings on most patents or printed publications – the limited bases upon which petitioner can rely in an IPR.  But a question remained, and contradictory district court decisions arose, as to whether petitioners would be estopped from relying on a prior art commercial product (known as “device art,” which could not itself have been raised in the IPR) even if a printed publication describing the product (i.e. a patent or technical manual) was available and presumably could have been raised. 

The two lines of district court decisions that developed regarding the application of IPR estoppel to device art diverged based on different interpretations of “grounds” as that term is used in the statute.  The first line of cases held that “grounds” refers to the legal theories of invalidity under §§ 102 and 103 and that estoppel did not therefore extend to device art being used to support a different invalidity “ground.”  In contrast, the second line of cases held that “grounds” refers to the specific prior art references that were relied upon and that estoppel did therefore apply to device art, so to prevent petitioners from simply “swapping labels” to avoid being estopped.   

On May 7, 2025, in Ingenico Inc. v. IOENGINE, LLC, the Federal Circuit finally provided much needed clarity and resolved the contradictory split of standards.  Following IPRs, Ingenico successfully challenged the asserted patents in district court based on a prior art device called the DiskOnKey system, asserting that the claimed inventions were anticipated or obvious due to prior use or sale of the system.  IOENGINE argued that Ingenico should have been estopped from presenting this theory because the prior art device was substantially the same as printed publications that could have been raised during the IPR. The Federal Circuit rejected this argument, determining that “grounds” as it is used in the statute refer to the legal theories of invalidity under §§ 102 and 103, not the specific prior art references. This interpretation embraces a narrower form of estoppel than many courts had been applying.

In view of this decision, patent challengers in the future are likely to seek out and rely more on commercial product prior art to support new invalidity theories in the district court or ITC following an IPR.  At the same time, we may see this decision influence the Patent Trial and Appeal Board’s approach to discretionary denials of IPR petitions, with a corresponding incentive for patent applicants to cite more of their own and others’ device prior art in Information Disclosure Statements to hedge against future IPR institution and/or to invoke potential estoppel.  If a party seeks to rely on printed publications related to commercial products in an IPR, it may need to stipulate not to pursue invalidity arguments based on the commercial products themselves post-IPR, in order to avoid discretionary denial.  While this is certainly a possibility, for the time being, the Federal Circuit appears to have given patent challengers greater flexibility in challenging patent validity beyond the confines of the IPR process.