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October 31, 2025
On October 17, 2025, the USPTO published a notice of proposed rulemaking (NPRM) that proposes new rules that would significantly limit the circumstances in which the PTAB can institute or maintain an IPR where the patent has already survived a validity challenge in another proceeding—or will soon undergo one.1
As explained below, the proposed rule changes would bar an IPR if the validity of the patent under 35 U.S.C. §§ 102 or 103 has previously been confirmed in an IPR, PGR, reexamination, district court litigation, ITC case or Federal Circuit appeal, or if a validity challenge based on prior art will be tried or decided in another proceeding before the PTAB’s final written decision deadline. The proposed rule changes also would require the petitioner to stipulate that it will not challenge the validity of the patent based on prior art in any other proceeding.
The USPTO’s stated purpose of the proposed rule changes is to “enhance fairness, efficiency, and predictability in patent disputes.”2 The proposed rule changes are designed to achieve this purpose by “focus[ing] inter partes review proceedings on patent claims that have not previously been challenged in litigation or where prior litigation was resolved at an early stage.”3
According the USPTO, subjecting patents to repeated validity challenges results in decreased reliability in a patent’s validity, even for “extremely strong patents.”4 The USPTO hopes the proposed rule changes will increase efficiency and fairness by reducing parallel and serial validity challenges.5
The USPTO asserts that the proposed rule changes will have a positive impact on the economy, increase innovation, and lower costs associated with litigation and patent licensing.6 The agency hopes that by drawing “clearer lines” around when an IPR should be instituted, parties can better determine, before filing, whether an IPR petition is likely to be instituted.7 The proposed rule changes would also serve to provide more time for the Administrative Patent Judges of the PTAB to focus on ex parte appeals in pending patent applications.8
The NPRM proposes adding four new rules (sections (d) to (g)) to 37 C.F.R. § 42.108, which governs the institution of IPRs.
I. Mandatory Stipulation Not to Pursue Prior Art Challenges In Other Proceedings
The first proposed rule (section (a)), entitled “Required stipulation for efficiency,” would provide that an IPR will not be instituted or maintained unless each petitioner files in the PTAB a stipulation stating that, if the IPR is instituted, the petitioner (and any real parties-in-interest and privies) will not challenge the validity or patentability of the patent under §§ 102 or 103 in any other proceeding.9 Each petitioner must also file such a stipulation in all the other proceedings in which the petitioner is litigating the patent.10
The only two types of prior art that may be used to challenge a patent in an IPR are patents and printed publications.11 However, the stipulation required under this proposed rule would prevent a petitioner from challenging validity under §§ 102 or 103 based on any type of prior art, including not only patents and printed publications but also public uses and on-sale bars based on products or systems. In other words, the required stipulation would be broader than the Sotera stipulation that petitioners may—and routinely do—voluntarily file, in which they agree not to pursue in the district court or ITC any invalidity challenges that were raised, or reasonably could have been raised, in the IPR, which are limited to those based on patents or printed publications.
II. No IPR If the Patent Has Already Survived a Prior Art Challenge
The second proposed rule (section (b)), entitled “Claims found valid in prior proceedings,” would provide that an IPR will not be instituted or maintained if the challenged claim (or an independent claim from which it depends) was previously found to be: (1) not invalid under §§ 102 or 103 by a district court or jury following a trial or in a summary judgment decision, or by the ITC in an initial or final determination; (2) not unpatentable under §§ 102 or 103 by the PTAB in an IPR or PGR final written decision; (3) patentable under §§ 102 or 103 by the examiner or PTAB in a reexamination filed by someone other than the patent owner (or a real party-in-interest or privy); or (4) patentable or valid under §§ 102 or 103 in a decision by the Federal Circuit that reversed a finding of unpatentability or invalidity.12
This proposed rule change would bar the PTAB from instituting or maintaining an IPR if the challenged claim has already survived a patentability or invalidity challenge based on prior art, even if the petitioner had no interest or involvement in that earlier challenge. In contrast, the existing IPR statutory estoppel applies only to the petitioner in the earlier IPR that resulted in a final written decision (and real parties-in-interest and privies), but not to any other, unrelated petitioners.13
Although this proposed rule would bar an IPR, it would not affect the petitioner’s ability to challenge validity in the district court or ITC. Nevertheless, the IPR bar created by this proposed rule may arguably be in tension with the general estoppel principle that the outcome of an earlier litigation does not preclude an unrelated non-party who did not have an opportunity to litigate the issues decided in that litigation.14 Moreover, the inclusion of a prior ITC validity determination as a trigger for this IPR bar may arguably be in tension with precedent that a validity decision by the ITC is not preclusive.15
III. No IPR If a Prior Art Validity Trial or Decision Is Likely To Occur Before the PTAB’s Final Written Decision Deadline
The third proposed rule (section (c)), entitled “Parallel Litigation,” would provide that an IPR will not be instituted or maintained if it is more likely than not that a district court trial, an ITC initial or final determination, or a PTAB final written decision in another IPR or PGR regarding the validity or patentability of the challenged claim (or an independent claim from which it depends) under §§ 102 or 103 will occur prior to the statutory deadline for the PTAB’s final written decision in the IPR.16
As worded, it appears that section (c) would be triggered by a future trial or decision in another proceeding regardless of whether the petitioner is a party to that other proceeding. However, if the petitioner is the only challenger in the other proceeding, the petitioner’s stipulation required by section (b) would prevent this IPR bar in section (c) from being triggered, because the stipulation will eliminate any validity or patentability challenge under §§ 102 or 103 in the other proceeding. Therefore, in practice, it appears that this IPR bar in section (c) would only apply when another party is challenging validity in the other proceeding and will proceed to a trial or decision before the final written decision deadline.
IV. Exception Permits Institution Only in Limited “Extraordinary Circumstances”
The fourth proposed change (section (d)), entitled “Institution in extraordinary circumstances,” would allow institution of an IPR, notwithstanding the previous proposed rules, if there are “extraordinary circumstances.”17
The examples of extraordinary circumstances set forth in this proposed rule are limited to “a determination by the Director that the prior challenge barring institution was initiated in bad faith, e.g., for the purpose of preventing future challenges, or that the prior challenge is rendered irrelevant in view of a substantial change in a statute or precedent of the Supreme Court of the United States.”18 In contrast, the proposed rule expressly states that new or additional prior art, new expert testimony, new legal argument, a prior challenger’s failure to appeal, and new caselaw that is not from the Supreme Court (which would include new Federal Circuit caselaw) would not be an extraordinary circumstance.19 In other words, a petitioner would not be able to pursue its own IPR even though it has mounted a better challenge with better prior art than the earlier, unsuccessful challenger, who may not have had the resources or incentive to do so.
The proposed rule also states that if a PTAB panel determines that extraordinary circumstances warrant institution, they will refer the case to the Director, who will personally decide whether to institute.20 However, on the same day that the USPTO published the NPRM, the Director issued a memorandum announcing that, effective October 20, 2025, the Director will personally decide whether to institute IPR and PGR petitions.21 Therefore, if the proposed rule in section (d) is adopted, presumably the Director will consider whether exceptional circumstances exist in the course of deciding whether to institute IPR petitions.
Finally, any frivolous or abusive petitions under this proposed rule may result in sanctions, including the grant of attorneys’ fees.22
If the USPTO adopts these proposed new rules, they would significantly limit the circumstances in which the PTAB can institute or maintain an IPR. An IPR would not be available if the patent has already survived a validity challenge based on prior art in the PTAB, a district court, the ITC or the Federal Circuit, or if the patent will be subject to such a prior art challenge that will be tried or decided before the PTAB’s final written decision deadline.
In particular, if adopted, the proposed rules may have a significant impact in the common scenario where a plaintiff asserts the same patent against several defendants.
Currently each unrelated defendant has an opportunity to defend against the infringement claims by filing its own IPR petition and moving to stay the litigation pending the outcome of the IPR. However, if the proposed rules are adopted, defendants sued for infringement of the same patent may be more likely to decide to band together to file one joint IPR petition, or a lead petition followed by copycat petitions with joinder motions.
Moreover, plaintiffs may be more likely to consider first suing one defendant with less resources or incentive to mount a robust validity challenge, and waiting to sue additional defendants until after the validity of the patent is confirmed in the initial litigation or IPR, or until that validity trial or decision will occur soon enough that it will be too late for the additional defendants to bring their own IPR petitions.
It appears that the intended effect of the proposed stipulation requirement would be to force patent challengers to choose one forum—either the PTAB or the parallel litigation—to present their invalidity challenge based on prior art. Defendants with strong product or system prior art may be more likely to decide to forego an IPR so that they can present all of their prior art in the litigation. On the other hand, defendants with strong prior art patents or printed publications may decide to forego all of their prior art invalidity defenses in the litigation so that they can pursue an IPR.
Finally, it is noteworthy that the proposed rules would not apply to PGR petitions and that no changes to PGR practice are proposed. This is consistent with the USPTO’s oft-stated view that PGR petitions are “favored” because they are filed within nine months of grant.23
The deadline to submit comments regarding the proposed rule changes is November 17, 2025. It seems likely that many stakeholders will submit comments given how significantly the proposed changes would alter IPR practice.