Estoppel limits of inter partes review


Financier Worldwide Magazine

April 2017 Issue

April 2017 Issue

When the America Invents Act (AIA) was enacted to include the new inter partes review (IPR) proceeding, stakeholders were focused on the estoppel provision and what that meant for future challenges to a patent by the petitioner. The estoppel provision prohibits a petitioner from later raising before the Patent Office, a district court or the US International Trade Commission, any ground of invalidity that the petitioner “raised or reasonably could have raised” during the IPR. IPR estoppel attaches when the Patent Trial and Appeal Board (PTAB) issues a final written decision – i.e., before the Federal Circuit has decided any appeals from the PTAB decision.

After enactment, many stakeholders believed IPR petitioners would have just one chance in the petition to make all their arguments that the patent is invalid, and that by challenging the patent before the PTAB, they would forfeit the chance to make that case later, based on prior art they were aware of or reasonably should have been aware of. A series of recent decisions have defined the estoppel provision as less stringent than stakeholders thought when the law was passed.

In two 2016 opinions, the Federal Circuit confirmed that the IPR estoppel provisions in Section 315(e) will not apply to invalidity grounds that the petitioner raised in the petition but the PTAB chose to not institute for redundancy. These opinions effectively limit estoppel to prior art on the grounds that the petitioner ‘could have raised’ after the institution of an IPR. The Federal Circuit’s focus was the wording of the statute, which is directed to grounds a petitioner raised or reasonably could have raised ‘during’ the IPR.

For example, in Shaw Indus. Group, Inc. v. Automated Creel Sys., Inc, the PTAB did not institute IPR based on the ground that claims were anticipated by the Payne reference, because that ground was redundant of other grounds. In the final written decision, the PTAB invalidated some of the challenged claims, based on the instituted grounds. Shaw appealed the PTAB’s decision, and also sought a writ of mandamus, requesting the Federal Circuit instruct the PTAB to institute based on the Payne reference. Shaw’s concern, among others, was that it would be estopped from using the Payne reference in future challenges to the patent based on Section 315(e). The Patent Office intervened and argued that Shaw’s interpretation was incorrect because “the denied ground never became part of the IPR”. In the end, the Federal Circuit agreed with the Patent Office.

Based on these Federal Circuit decisions and others, petitioners have been able to successfully argue that any non-instituted prior art challenge cannot give rise to estoppel, because the rejected ground would not be one the petitioner “raised or reasonably could have raised” during that IPR proceeding.

For example, in Princeton Digital Image Corporation v. Harmonix Music Systems Inc. et al., the patent owner moved to dismiss the defendant’s invalidity counterclaim due to estoppel under Section 315(e). More specifically, the defendant was a petitioner in two IPR proceedings; however, neither IPR resulted in a final written decision as to the validity of certain challenged claims. The patent owner unsuccessfully argued the defendant was estopped from arguing invalidity based on prior art that was raised in the IPR proceedings. The court held that since there was no final written decision as to the challenged claims, there was no estoppel.

Courts have gone a step further holding that estoppel does not apply to prior art that was never presented to the PTAB, but could have been based upon the prior art’s public nature. For example, in Intellectual Ventures I LLC et al. v. Toshiba Corporation et al., Judge Robinson addressed a summary judgment motion that involved invalidity challenges as to prior art references that were raised during an earlier IPR and others that arguably could have been raised in the IPR, but were not. Due to the IPR estoppel, the court granted the motion for the references instituted in the IPR proceeding but denied the motion as to the ones that could have been raised. Citing Shaw, the court stated that “[a]lthough [plaintiff’s] argument in this regard is perfectly plausible, in the sense that [defendant] certainly could have raised these additional obviousness grounds based on public documents at the outset of their IPR petition, the Federal Circuit has construed the above language quite literally”.

Even with several Federal Circuit decisions on estoppel, there is still much uncertainty regarding the exact implications of the estoppel provision of Section 315(e). It is critical to remain aware of that when making decisions regarding the scope of estoppel.


R. David Donoghue and Steven E. Jedlinski are partners and Anthony J. Fuga is an associate at Holland & Knight. Mr Donoghue can be contacted on +1 (312) 578 6553 or by email: Mr Jedlinski can be contacted on +1 (312) 715 5818 or by email: Mr Fuga can be contacted on +1 (312) 715 5771 or by email:

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R. David Donoghue, Steven E. Jedlinski and Anthony J. Fuga

Holland & Knight

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