On May 7, 2025, the Federal Circuit weighed in on a long-unanswered question regarding the scope of estoppel arising from inter partes review (IPR). In Ingenico Inc. v. IOENGINE, LLC,the Court held that estoppel from a final written decision does not preclude reliance on patents or other printed publications to assert invalidity at trial on grounds (such as the on-sale bar) that could not have been raised in an IPR. The Court's holding has the potential to significantly narrow the preclusive effect of IPRs on validity arguments in parallel district court litigation.
Background
The case arose from a declaratory judgment action filed in the District of Delaware by Ingenico regarding U.S. Patent Nos. 9,059,969 and 9,774,703 (the asserted patents), directed to portable devices allowing communications with a network server in response to user interaction. Before trial, Ingenico filed IPR petitions, which resulted in final written decisions of unpatentability for most, but not all, of the challenged claims of the asserted patents.
Ingenico maintained invalidity defenses in the DJ action as to the remaining claims, relying on the public use and sale of the DiskOnKey Device by M-Systems Flash Disk Pioneers Ltd. Ingenico did not submit any documentation related to the DiskOnKey Device with its IPR petitions. Nonetheless, IOENGINE moved on summary judgment to preclude Ingenico from using documents describing the device, based on the estoppel provisions of 35 U.S.C. § 315(e).
Judge Bryson, sitting in Delaware by designation from the Federal Circuit, ruled the documents admissible "to the extent... that they form part of a substantively different combination of references that could not reasonably have been raised in the IPRs." At trial, Ingenico presented invalidity evidence, including documentation associated with the DiskOnKey Device. The jury subsequently returned a verdict invalidating the claims of the asserted patents as anticipated or obvious. IOENGINE filed a motion for judgment as a matter of law of no invalidity, which the district court denied.
Federal Circuit Decision
On appeal, IOENGINE challenged the jury's finding that the DiskOnKey Device was "in public use." In the alternative, IOENGINE argued it was entitled to a new trial on the ground that Ingenico should have been estopped from presenting its documentary evidence at trial under 35 U.S.C. § 315(e). It argued that IPR estoppel should have applied because the documentary evidence relied on by Ingenico was "entirely cumulative and substantively identical" to printed publications that reasonably could have been raised during the IPR.
The Federal Circuit acknowledged that it had not previously interpreted the term "ground" in the context of the estoppel provision of 35 U.S.C. § 315, and noted the split among district courts on the issue. The Court analyzed the statutory language and Congressional intent, and attached significance to Congress's decision to limit the available invalidity "grounds" in an IPR to "prior art consisting of patents or printed publications." The Court noted that Congress could have precluded petitioners from asserting any "prior art" that could have been raised in an IPR, but instead only precluded petitions from asserting a "ground" that could have been raised. Noting this distinction between estopped "grounds" and estopped "prior art," the Court determined that IPR estoppel does not prevent a petitioner from using the same prior art raised in an IPR to assist in asserting grounds that could not be raised during the IPR.
Takeaways
The Federal Circuit's ruling in Ingenico conflicts with a number of district court decisions, particularly in Delaware, that broadly interpreted the estoppel statute to preclude prior art documents that could have been raised as printed publications in an IPR. The decision provides IPR petitioners with a clear roadmap for the use of documentary evidence to make invalidity attacks in parallel district court litigation. Given its potential significance in resolving a split among district courts, it will come as no surprise if the Federal Circuit agrees to rehearing en banc to provide more thorough consideration on the issue.
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