June 2025 Ingenico Inc. vs IOENGINE, LLC is a decision issued on 7 May 2025 by the US Federal Circuit to narrow the scope of Inter Partes Review (IPR) estoppel under Chapter 35 Section 315(e)(2) of the US Code. This decision comes after a long-term divide between the US District Courts.
The Federal Circuit held that, although the defendant (Ingenico) had previously challenged IOENGINE’s patents in IPRs, they were not precluded from relying on product prior art and printed publications related thereto to prove the claimed invention was known or used by others, on sale, or in public use at the time of filing.
Section 315(e)(2) states that if a party has received a final written decision addressing the patentability of a claim during IPR proceedings, they are prevented from later arguing, before the District Court, that claim is invalid “on any ground that the petition raised or reasonably could have raised” during the IPR proceedings.
This statute was the cause of a long-standing divide between the District Courts, because the prior art which can be brought forward in IPRs is limited to patents and printed publications, hence the statute was not clear whether the estoppel extended to product art.
Some District Courts held took the view that parties are precluded from bringing invalidity grounds based on product art that is materially identical to printed publications which could have been raised during an IPR and other District Courts held that the estoppel does not apply to product art because product art cannot be brought forward in IPRs.
In this decision, the Federal Circuit have clarified the statute by affirming that IPR estoppel did not apply to the defendant’s invalidity grounds, which were based on product art and related printed publications. Hence, the defendant (Ingenico) was not prevented from relying on product art and related printed publications to advance invalidity grounds that could not have been raised during the earlier IPRs.
The Federal Court have, therefore, taken a decision to narrow the scope of estoppel under Section 315(e)(2) by confirming that Section 315(e)(2) “does not preclude a petitioner from relying on the same patents and printed publications as evidence in asserting a ground that could not be raised during the IPR, such as that the claimed invention was known or used by others, on sale, or in public use”.
In their reasoning for the decision, the Federal Circuit confirmed that the use of the term “ground” in the statute should be interpreted as meaning “theories of invalidity available to challenge a claim”, whereas the term “prior art” refers to “evidence of a ground” and is “not coextensive with a ground.”
In view of this decision, the District Courts will now be required to consider invalidity grounds which rely on product prior art to show that a claimed invention was known or used by others at the time of filing, regardless of whether the evidence supporting said invalidity grounds was raised or reasonably could have earlier been raised in an IPR.
