Inter Partes Review (IPR) Archives

Inter Partes Review (IPR)

Use of general knowledge in IPR petitions will no longer work

by Ashley K. Justice | Aug 14, 2025 | Patents

On July 31, 2025, the US Patent & Trademark Office (PTO) issued a memo clarifying the requirements under 37 C.F.R. § 42.104(b)(4) for inter partes review (IPR) petitions. The memo emphasizes that petitioners must clearly identify where each element of the challenged claims is found in the prior art patents or printed publications relied upon.

Historically, the Patent Trial & Appeal Board permitted petitioners to rely on applicant admitted prior art (AAPA), expert testimony, common sense, and other forms of general knowledge to fill in missing claim limitations. However, the new guidance states that such general knowledge, including AAPA, can no longer be used to supply missing claim elements. If an IPR petition relies on general knowledge to bridge gaps in the prior art, the Board will now deny institution.

The memo clarifies that § 104(b)(4) does not limit the use of general knowledge to support a motivation to combine or to demonstrate the knowledge of a person of ordinary skill in the art. However, § 104(b)(4) may be narrower than 35 U.S.C. § 311(b). Just weeks before the memo was issued, the US Court of Appeals for the Federal Circuit’s decision in Shockwave Medical. v. Cardiovascular Systems held that AAPA can be used to supply missing claim limitations without violating § 311(b), highlighting a potential tension between the rule and judicial interpretation.

The PTO’s new requirements will apply to all IPR petitions filed on or after September 1, 2025.

Practice note: To meet the threshold for institution, IPR petitioners should ensure that each claim element is explicitly mapped to prior art patents or printed publications. Reliance on general knowledge to fill in missing elements will no longer be sufficient.

Collateral estoppel remains inapplicable to unchallenged IPR claims

by Courtney Seams | Aug 14, 2025 | Patents

Returning to its decision in Kroy IP, the US Court of Appeals for the Federal Circuit denied a petition for panel rehearing and rehearing en banc, leaving undisturbed its prior opinion that collateral estoppel does not apply to the assertion of claims from a patent, even when other patentably indistinct claims from that patent have been found unpatentable in inter partes review (IPR) proceedings before the Patent Trial & Appeal Board. Kroy IP Holdings, LLC v. Groupon, Inc., Case No. 23-1359 (Fed. Cir. Aug. 1, 2025) (per curiam) (Moore, J., concurring) (Dyk, J., dissenting).

Kroy sued Groupon for patent infringement, and Groupon subsequently filed two IPR petitions. The Board ultimately found 21 of the asserted claims unpatentable. Kroy amended its complaint to remove those 21 claims and proceed only with claims that were not at issue in the IPR proceedings. Groupon moved to dismiss the complaint, arguing that Kroy was collaterally estopped from asserting the remaining claims because of the Board’s prior IPR rulings finding other patentably indistinct claims unpatentable. The district court agreed with Groupon, finding that the remaining asserted claims were not materially different from the unpatentable claims in terms of validity and granted the motion to dismiss with prejudice. Kroy appealed.

The Federal Circuit held that a Board determination finding certain patent claims unpatentable under the preponderance of the evidence standard did not collaterally estop Kroy from asserting other unreviewed claims of the same patent in district court litigation against Groupon. Groupon subsequently petitioned for panel rehearing and rehearing en banc, both of which the Federal Circuit denied per curiam.

Chief Judge Moore, joined by Judge Stoll, concurred in the decision. In her concurring opinion, Judge Moore explained that collateral estoppel does not apply where differing standards of proof exist (namely, the preponderance of evidence standard used by the Board versus the clear and convincing evidence standard applied in district courts) because this difference can materially affect a patent’s validity determination. She emphasized that collateral estoppel should apply consistently in patent cases and cautioned against deviating from the established collateral estoppel standards. Judge Moore also noted that policy concerns are mitigated by the ability to file a second IPR petition, because the Board is likely to grant review where a petition raises a substantially similar question of invalidity.

Judge Dyk, joined by Judge Hughes, dissented from the decision. The dissent advocated departing from the traditional burden-of-proof rule applicable in the collateral estoppel context to avoid duplicative litigation regarding patent validity. The dissent argued that the majority opinion conflicted with the Federal Circuit’s 2018 opinion in XY, LLC v. Trans Ova Genetics, which held that collateral estoppel extends between Board decisions and district court proceedings in pending or co-pending actions. According to the dissent, the majority’s approach permits repeated litigation of the validity of patent claims previously found unpatentable in IPR proceedings affirmed on appeal. The dissent expressed concern that applying collateral estoppel in this manner would enable patentees to evade the preclusive effect of adverse IPR [...]

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Game over: Prior interference doesn’t preclude IPR proceeding

by Joshua Revilla | Jul 31, 2025 | Patents

The US Court of Appeals for the Federal Circuit affirmed a Patent Trial & Appeal Board unpatentability determination during an inter partes review (IPR) proceeding, concluding that the Board’s decision to not apply interference estoppel fell within the general rule of unreviewability. IGT v. Zynga Inc., Case No. 23-2262 (Fed. Cir. July 22, 2025) (Prost, Reyna, Taranto, JJ.)

IGT owns an expired patent that addresses the need for gaming machines, such as slot machines and video poker machines, to securely communicate over a public network. The patent was issued in January 2007 from an application filed in April 2002 and published in August 2002. Zynga filed a patent application on August 21, 2003, that included claims copied from IGT’s published application.

In March 2010, the US Patent & Trademark Office (PTO) Board of Patent Appeals & Interferences (predecessor of the Patent Trial & Appeal Board, which Congress created in 2011) declared an interference proceeding between Zynga’s application and IGT’s patent. During the interference proceeding, Zynga argued IGT’s patent was obvious over three pieces of prior art. IGT argued that Zynga lacked standing because the claims in Zynga’s application were unpatentable for a lack of written description. The Board granted IGT’s motion for judgment on the “threshold issue” that Zynga’s application lacked adequate written description support, terminated the interference with a judgment against Zynga, and dismissed the motion that the claims were unpatentable as moot.

In April 2021, IGT sued Zynga alleging infringement of six patents, including the patent that was subject to the interference proceeding. Zynga filed an IPR petition for that patent, asserting obviousness based on new prior art. In its preliminary response, IGT argued that the Board should deny institution based on interference estoppel under 37 C.F.R. § 41.127(a)(1) because Zynga could have raised the newly asserted art in the interference proceeding. The Board rejected IGT’s interference estoppel arguments because:

The interference was terminated based on the “threshold issue” of lack of written description and therefore the Board did not analyze or decide any issues of unpatentability.
It would be unfair to estop Zynga, and to the extent that estoppel applied, the Board waived its application under 37 C.F.R. § 42.5(b).

IGT requested rehearing and precedential opinion panel review, arguing that interference estoppel barred institution. The PTO Director affirmed the Board’s decision, stating that interference estoppel under § 41.127 did not apply because IPR proceedings are governed by 37 C.F.R. pt. 42, which does not incorporate Part 41 or its estoppel provisions. The PTO Director also noted that the Board’s termination was based on a threshold issue. The Board proceeded with the review and ultimately concluded that all the challenged claims were unpatentable as obvious. IGT appealed.

IGT argued that the Board and PTO Director erred in ruling that interference estoppel did not bar the petition and challenged the Board’s holding that the claims would have been obvious over the newly asserted prior art.

The Federal Circuit concluded that the interference estoppel determination fell within the [...]

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Applicant-admitted prior art may inform but can’t be basis for IPR challenges

by Ashley K. Justice | Jul 24, 2025 | Patents

The US Court of Appeals for the Federal Circuit clarified that while applicant-admitted prior art (AAPA) may be cited as evidence of general background knowledge in inter partes review (IPR) proceedings, it cannot serve as the basis for an IPR ground. The Court also confirmed that the petitioner had Article III standing to cross-appeal based on concrete plans for future activity. Shockwave Medical, Inc. v. Cardiovascular Systems, Inc., Case No. 23-1864 (Fed. Cir. July 14, 2025) (Lourie, Dyk, Cunningham, JJ.)

Shockwave Medical owns a patent directed to treating atherosclerosis using a balloon catheter in combination with shockwaves generated by electrodes and a pulse generator. The patent specification acknowledged that “over-the-wire angioplasty balloon catheters” were well known in the art. Cardiovascular Systems, Inc. (CSI) filed an IPR petition asserting that it would have been obvious to modify a European patent application with the angioplasty balloon catheter disclosed in the AAPA.

The Patent Trial & Appeal Board found all but one claim unpatentable as obvious, relying on the AAPA solely as evidence of background knowledge. Both parties appealed.

Shockwave challenged the Board’s reliance on the AAPA, arguing that 35 U.S.C. § 311(b) prohibits using AAPA as a basis for an IPR petition. The Federal Circuit disagreed, reaffirming its prior decisions in Qualcomm I and Qualcomm II. In Qualcomm I, the Court explained that AAPA cannot be the basis of a ground in an IPR petition but can be evidence of background knowledge. In Qualcomm II, the Court found that the Board erred in determining that the use of AAPA was proper when the petitioner expressly included AAPA in one of its grounds. Relying on these decisions, the Court explained that while AAPA cannot form the basis of a ground in an IPR petition, it may be used to demonstrate the general knowledge of a person of ordinary skill in the art and to supply missing claim limitations.

Shockwave pointed to a table in the Board’s final written decision listing AAPA under “reference(s)/basis” as evidence that the Board improperly relied on AAPA as a ground. The Federal Circuit rejected this argument, distinguishing Qualcomm II and emphasizing that the petitioner, not the Board, defines the grounds for review. Because CSI did not rely on AAPA as a ground, its use was permissible.

CSI cross-appealed the Board’s finding that one claim was not obvious. Shockwave challenged CSI’s standing, but the Federal Circuit found that CSI had Article III standing because it had concrete plans to begin clinical trials and because of Shockwave’s public statements suggesting it would assert the patent. The Court concluded that these facts created a substantial risk of future infringement.

On the merits, the Federal Circuit agreed with CSI that the Board erred by failing to consider the prior art as a whole. The Court reiterated that the obviousness inquiry requires evaluating the combined teachings of the prior art, not individual references in isolation. Finding no evidence to support the Board’s conclusion, the Court reversed the Board’s decision as to the remaining [...]

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Prosecution history primacy: “Consisting essentially of” means what applicant said it meant

by Peter Marston | Jul 10, 2025 | Life Sciences, Patents

In a decision that underscores the primacy of prosecution history to determine claim scope, the US Court of Appeals for the Federal Circuit reversed the Patent Trial & Appeal Board’s interpretation of the transitional phrase “consisting essentially of,” holding that the patentee’s actions during prosecution narrowed the claims beyond the conventional construction. Eye Therapies, LLC v. Slayback Pharma, LLC, Case No. 23-2173 (Fed. Cir. June 30, 2025) (Scarsi, Dist. J., by designation; Taranto, Stoll, JJ.)

The case involved a method for reducing eye redness using low concentrations of brimonidine, a vasoconstrictive compound. Eye Therapies owns a patent that claims methods of administering brimonidine “consisting essentially of” the active ingredient. During inter partes review (IPR), the Board applied the typical construction of that transitional phrase, allowing for the presence of other active agents as long as they did not materially affect the invention’s basic and novel properties. Based on that reading, the Board found the claims obvious over prior art references that disclosed brimonidine in combination with other drugs. On appeal, Eye Therapies argued that the Board’s construction was too broad and inconsistent with the prosecution history.

The Federal Circuit agreed. Although “consisting essentially of” is generally understood to permit unlisted ingredients that don’t materially affect the invention, the Court emphasized that this meaning can be overridden by the intrinsic record. In this case, the applicant amended the claims to avoid prior art and repeatedly argued that the invention involved only brimonidine, with no other active agents. During the original prosecution, the examiner allowed the claims on that basis. The Court found these statements to be definitional, particularly in light of the applicant’s use of “i.e.” to equate the claim language with a brimonidine-only method. Given the clarity and consistency of the applicant’s position, the Court concluded that the prosecution history required a narrower reading than the one the Board used based on the phrase’s conventional meaning.

The Federal Circuit acknowledged that the patent specification disclosed embodiments containing additional active agents. That alone, however, did not justify a broader construction. The narrowing amendment came after the specification was drafted, and the Court reiterated that not every embodiment must fall within the scope of the claims, particularly when the claims have been narrowed during prosecution. The Court also noted that other embodiments in the specification were fully consistent with the narrower interpretation. Taken together, these factors reinforced the conclusion that the applicant’s prosecution statements – not the broader illustrative disclosures – defined the proper scope of the claims.

The Federal Circuit distinguished its 2009 decision in Ecolab v. FMC, where it declined to apply prosecution history disclaimer despite similar language. In Ecolab, the patentee initially stated that peracetic acid was the “sole antimicrobial agent,” but the examiner clarified that “consisting essentially of” did not mean “solely.” The applicant never repeated the statement and secured allowance on other grounds. The specification in Ecolab also described compositions that included other known antimicrobial agents, which supported the broader interpretation. In contrast, the applicant here amended the claims, consistently [...]

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Seeing double? Director instructs Board to resolve claim construction pre-institution

by Benjamin Ediger, Ph.D. | Jul 2, 2025 | Patents

The acting director of the US Patent & Trademark Office (PTO) vacated and remanded a Patent Trial & Appeal Board decision to institute two inter partes review (IPR) petitions that challenged the same claims. The acting director determined that the two petitions primarily differed with respect to claim construction. In a decision designated as “informative,” he authorized the Board to resolve claim construction pre-institution in view of the Consolidated Trial Practice Guide’s (CTPG) direction that “one petition should be sufficient to challenge the claims of a patent in most situations.” CrowdStrike, Inc. v. GoSecure, Inc., IPR2025-00068; -00070 (PTAB June 25, 2025) (Stewart, Act. Dir.) The PTO designates a decision as informative when it provides “norms on recurring issues, guidance on issues of first impression to the Board, guidance on Board rules and practices, and guidance on issues that may develop through analysis of recurring issues in many cases.”

CrowdStrike submitted two IPR petitions that challenged the same claims of GoSecure’s patent. The Board instituted both IPRs. GoSecure requested director review, asserting that instituting both petitions was an abuse of the Board’s discretion. On review, the acting director determined that the Board abused its discretion in view of the CTPG’s direction.

The acting director concluded that the two petitions did not reflect an exception to the CTPG’s direction. He determined that CrowdStrike’s petitions were primarily distinguished by the constructions applied to a claim term. The acting director explained that the Board should have construed the term at issue prior to granting institution, concluding that the Board’s institution decision amounted to improper expansion of CrowdStrike’s permitted word count and placed a substantial and unnecessary burden on the Board and GoSecure that could raise fairness, timing, and efficiency concerns. The acting director vacated and remanded the Board’s institution decision.

The acting director also instructed the Board that the patent owner should be allowed to “submit whatever arguments are necessary for the panel to make a claim construction determination” even if the patent owner has not addressed the issue.

Looks like estoppel, sounds like estoppel … but it’s just director discretion

by Amol Parikh | Jun 26, 2025 | Patents

The acting director of the US Patent & Trademark Office (PTO) granted a patent owner’s request for discretionary denial and denied institution of an inter partes review (IPR) proceeding, finding that the petitioner engaged in unfair dealings by challenging a patent on which its employees were the inventors. Tessell, Inc. v. Nutanix, Inc., IPR2025-00322 (PTAB June 12, 2025) (Stewart, Act. Dir.)

Four individuals were Nutanix employees when they invented the subject matter of the challenged patent. Two of the individuals left to form Tessell and later hired the other two. Tessell, which now includes nearly all of the inventors of the challenged patent, filed a petition for IPR arguing that the claims of the patent were unpatentable. Nutanix filed a request for discretionary denial, which Tessell opposed.

The doctrine of assignor estoppel generally prevents an inventor who has sold or assigned a patent from challenging the validity of the patent. Although assignor estoppel does not apply in IPR proceedings, the acting director explained that the PTO may consider unfair dealings as a factor when determining whether to exercise discretion to deny institution under 35 U.S.C. § 314(a). The acting director found that it was inappropriate for the inventors to have used PTO resources to obtain a patent only to later advocate for its unpatentability. The acting director therefore exercised discretion to deny institution.

Designated Informative: PTO Director Declines IPR Institution Following District Court § 101 Invalidation

by Jodi Benassi | May 15, 2025 | Patents

The US Patent & Trademark Office (PTO) designated a recent Director Review decision as informative, signaling its significance for future proceedings. The decision emphasizes that a final district court ruling invalidating a patent weighs heavily against instituting inter partes review (IPR) under the Fintiv framework, reinforcing the agency’s stance on minimizing duplicative litigation. Hulu LLC v. Piranha Media Distribution LLC, IPR2024-01252; -01253 (PTAB Director Review Apr. 17, 2025) (Stewart, PTO Dir.)

Piranha requested Director Review of the Patent Trial & Appeal Board’s decision granting institution of two IPRs filed by Hulu. Piranha argued that the decision should be reversed and the IPRs denied institution, citing a district court final judgment invalidating the challenged claims under 35 U.S.C. § 101 issued before the institution decision was made. Hulu argued that Director Review was unwarranted.

In the district court litigation, Piranha asserted that Hulu infringed claims from two patents related to integration of advertising content into digital media streams. Hulu moved to dismiss the complaint, arguing that the asserted patents were ineligible for patenting under § 101. The district court determined that the asserted claims were directed to the abstract idea of “displaying an advertisement in exchange for access to copyrighted material, as well as the abstract idea of receiving, organizing, and displaying data,” and contained no inventive concept. The district court granted Hulu’s motion to dismiss and held the claims patent ineligible and therefore invalid under § 101.

The Director explained that since a district court had already ruled the patent claims invalid, launching separate IPRs to assess their patentability on other grounds was unnecessary. The Director noted that if the Federal Circuit overturned the district court’s decision, Hulu could still pursue its invalidity arguments during remand proceedings. Declining to institute review was the more efficient and practical path under the circumstances, the Director said.

While the Board applied the Fintiv framework in its institution decision, the Director observed that the framework does not align neatly with the facts of this case, where a final district court judgment under § 101 preceded the Board’s decision. The Director ultimately concluded that a second review proceeding was unwarranted given the claims’ current invalid status.

Breaking New Grounds to Limits of IPR Estoppel

by Amol Parikh | May 15, 2025 | Patents

In a matter of first impression, the US Court of Appeals for the Federal Circuit found that inter partes review (IPR) estoppel does not preclude a petitioner from relying on the same patents and printed publications as evidence in asserting a ground that could not have been raised during the IPR proceeding, such as that the claimed invention was known or used by others, on sale, or in public use. Ingenico Inc. v. IOENGINE, LLC, Case No. 23-1367 (Fed. Cir. May 7, 2025) (Dyk, Prost, Hughes, JJ.)

IOENGINE owns patents directed to a portable device, such as a USB thumb drive, that includes a processor that causes communications to be sent to a network server in response to user interaction with an interface on a terminal. Ingenico filed a declaratory judgment action against IOENGINE after one of Ingenico’s customers was sued for infringement based on Ingenico’s products. Ingenico filed IPR petitions challenging the asserted patents, which resulted in final written decisions that held most of the challenged claims unpatentable.

Back at the district court, IOENGINE proceeded with the remaining claims. At summary judgment, IOENGINE moved, under 35 U.S.C. § 315(e)(2), to preclude Ingenico from relying on “documentation related to DiskOnKey Upgrade software,” arguing that Ingenico reasonably could have been expected to raise that prior art during the IPR proceedings. The district court ruled that “Ingenico will be estopped from relying on those documents [to prove invalidity] except 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 introduced evidence of a prior art USB device known as the DiskOnKey. The DiskOnKey device was offered with various software applications, including an application called Firmware Upgrader, and was equipped with capabilities described in a Software Development Kit (together, the DiskOnKey system). Ingenico argued that the DiskOnKey system invalidated the asserted claims as anticipated or obvious because it was either “on sale” or “in public use” under 35 U.S.C. § 102(b), or “known or used by others . . . before the date of the invention” under 35 U.S.C. § 102(a). The jury returned a verdict finding the patents were infringed but invalid as anticipated and obvious. Both parties appealed.

IOENGINE did not dispute the jury’s finding that the DiskOnKey system invalidated the claims-at-issue as anticipated or obvious if the DiskOnKey system was prior art, but instead argued that the jury’s finding that the Firmware Upgrader portion of the DiskOnKey system was either “on sale” or “in public use,” or “known or used by others . . . before the invention.”

The Federal Circuit found that the jury’s finding that the Firmware Upgrader was accessible to the public was supported by substantial evidence. Specifically, Ingenico had introduced a press release promoting the launch of the Firmware Upgrader and a website from which the Firmware Upgrader was available for download. IOENGINE argued that this evidence did not show actual use, but the Court rejected [...]

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Collateral Estoppel Doesn’t Apply to Unchallenged IPR Claims

by Jodi Benassi | Feb 20, 2025 | Patents

The US Court Appeals for the Federal Circuit found that despite a Patent Trial & Appeal Board determination that certain challenged patent claims were unpatentable based on a preponderance of the evidence standard, the patent owner is not collaterally estopped from asserting other, unreviewed claims of that patent in district court litigation. Kroy IP Holdings, LLC v. Groupon, Inc., Case No. 23-1359 (Fed. Cir. Feb. 10, 2025) (Prost, Reyna, Taranto JJ.)

Kroy sued Groupon for patent infringement. In response, Groupon filed two inter partes review (IPR) petitions challenging 21 claims of the patent at issue. After Groupon’s IPR deadline passed, Kroy amended its complaint to add additional claims from the challenged patent. The Board found all 21 challenged claims unpatentable. Kroy amended its complaint again, this time removing the 21 unpatentable claims and including only claims that were not at issue in the IPR proceedings.

In response, Groupon moved to dismiss the complaint, arguing that the Board’s prior IPR rulings on the unpatentable claims collaterally estopped Kroy from asserting the new claims. The district court agreed, finding that if the Board issues final judgment that a patent claim is unpatentable and another claim is immaterially different, then collateral estoppel applies to that other claim for purposes of invalidity. Applying that standard, the district court determined that the new claims were not materially different from the unpatentable claims in terms of invalidity and granted Groupon’s motion to dismiss with prejudice. Kroy appealed.

Kroy argued that collateral estoppel should not apply because the burden of proof for invalidity in an IPR proceeding (preponderance of the evidence) is lower than in the district court (clear and convincing). The Federal Circuit noted that this case presents a distinct question of collateral estoppel law; that is, whether a prior final written decision of the Board that certain patent claims are unpatentable precludes a patentee from asserting other claims from the same patent, even assuming the asserted claims are immaterially different from the unpatentable claims for purposes of invalidity.

Referring to its recent 2024 decision in ParkerVision v. Qualcomm, the Federal Circuit clarified that collateral estoppel does not apply to new claims that have not yet been adjudicated. The Court explained that Groupon must prove the invalidity of these new claims in the district court by clear and convincing evidence. The Court dismissed Groupon’s reliance on the 2013 Ohio Willow Wood decision, noting that this case addressed whether a prior district court’s invalidity ruling estopped the patentee from asserting claims in the district court that are immaterially different for purposes of invalidity. On the other hand, the Ohio Willow Wood estoppel scenario occurred in district courts involving the same burden of proof. Because the Board determined unpatentability on separate patent claims based on a preponderance of the evidence standard, courts cannot collaterally estop a patentee from asserting other, unadjudicated patent claims in district court litigation.

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