The USPTO’s recently published notice of proposed rulemaking (RIN 0651-AD89, Docket No. PTO-P-2025-0025) for inter partes review (IPR) proceedings seeks to curb multiple IPR challenges to the same patent. This aligns with the USPTO’s recent and decisive shift toward limiting accessibility of IPRs as a means to challenge patents outside of the district courts. While the USPTO claims to promote “fairness, efficiency, and predictability,” the practical impact would be a dramatic change in the risk calculus for accused infringers—especially those who never had their own opportunity to mount a proper challenge. Parties would be stuck with the results of someone else’s work product, no matter how flawed it was. For purposes of §§ 102/103, the USPTO effectively seeks to move beyond the presumption of validity and create a final determination of validity as far as IPR challenges are concerned.
The Rules at a Glance
The proposed amendments to 37 CFR §42.108 are, in short, designed to:
- Require stipulations from petitioners not to pursue invalidity under §§ 102/103 in other venues if IPR is instituted. (§42.108(d))
- Prohibit institution of IPRs against claims that have survived validity challenges in district court, ITC, or prior USPTO proceedings. (§42.108(e))
- Prohibit institution if a district court trial or ITC initial or final determination will occur, more likely than not, prior to the final written decision in the instant IPR challenge. (§42.108(f))
- Disallow second bites at the apple, unless “extraordinary circumstances” exist—such as bad faith or statutory changes and providing the threat of sanctions and attorneys’ fees for frivolous or abusive petitions. (§42.108(g))
The proposed amendments represent a significant departure from current jurisprudence.
The new requirement for petitioners to provide binding stipulations goes well beyond the current estoppel provisions of §315(e) and the current practice of Sotera stipulations. The new stipulation requirement would: (i) be triggered based on institution rather than a final written decision; and (ii) appear to foreclose any validity challenges under §§ 102/103, not just those raised or that could have been raised in the IPR. As set forth in a Prior Post, the Federal Circuit recognizes the limits on §315(e) estoppel and allows certain 102/103 validity challenges in the district court—the proposed rules threaten to foreclose these alternative challenges.
The prohibition on subsequent challenges goes beyond §325(d) by providing a mandatory bar to IPR institution if the claims were upheld under §§ 102/103 in district court, ITC, or prior USPTO proceedings. Nothing is left to the discretion of the panel based on relevant circumstances.
The parallel-proceedings prohibition does more than codify Fintiv’s discretionary factors. Instead of applying discretionary denial, the proposed regulation strictly prohibits institution when a parallel proceeding on validity is expected to resolve before the Patent Trial and Appeal Board’s (PTAB’s) deadline for a final written decision. Also, the “more likely than not” standard closes the door to institution even where uncertainty in timing, potential delays, or the possibility of a stay exists.
The “extraordinary circumstances” exception is sharply limited under the proposed rule and would allow a second IPR challenge only in rare cases like prior bad faith or major legal shifts—no longer for new evidence or prior error.
The intent is plain and the effect severe: once a claim has already faced a validity challenge, further access to the IPR process is sharply restricted. As a result, IPRs will no longer serve as a meaningful alternative to more expensive district court litigation in cases where prior challenges have been mounted, effectively closing the door to PTAB review for many parties.
Where Is the Fairness?
The USPTO claims the new rules promote fairness. But what happens when someone else’s “first bite” at challenging a patent was, well, just plain bad?
Under the draft rule, if a prior court or USPTO proceeding failed to invalidate a claim, later petitioners are out of luck. The process is “one and done”—but what if the first challenger:
- Settled early without properly responding to patent owner responses and the final written decision is based on one-sided arguments;
- Failed to marshal the best prior art or arguments due to resource constraints or word-count limits;
- Presented poor expert analysis or legal argument; or
- Simply botched the challenge due to lack of skill or experience?
The consequences are clear. A subsequent party who may have superior resources, stronger art, or a better perspective on the claims could be forever barred from seeking PTAB review. In effect, every patent challenged once must be presumed finally adjudicated, regardless of the quality of the prior proceeding. Subsequent challengers are effectively barred from choosing their own counsel and experts, choosing their own art, and crafting their own challenges. They are instead stuck with decisions they played no part in.
But fairness to the USPTO in this instance does not translate to fairness to the targets of litigation campaigns. This shift is particularly concerning in the context of non-practicing entities (NPEs), who are notorious for filing large numbers of lawsuits and leveraging early settlements. Their business model frequently relies on asserting patents of questionable value against numerous defendants. Under the proposed “one and done” rules, if a patent troll’s claims survive an initial, potentially superficial challenge, or are settled before petitioner replies are filed and still reach final written decision, subsequent defendants will most likely be deprived the opportunity to seek their own IPR. This will embolden abusive litigation tactics and allow dubious patents to remain untested, putting a heavy burden on innovators and legitimate businesses facing repeated, specious claims.
The reality is that mounting a successful IPR challenge is an art as much as a science. Current word and page limits, both at the PTAB and in district courts, often force challengers to strategically triage their arguments. Important references and compelling lines of attack may be omitted or underdeveloped—not because they lack merit, but simply due to restrictive filing constraints. This means that even strong invalidity arguments can end up neglected, increasing the risk that an incomplete or inadequate challenge will become the final word on a patent’s validity.
Also, the proposed approach overlooks the reality that the USPTO sometimes makes errors. Patent examination and review is a highly complex and sometimes subjective process. The USPTO is given limited resources to evaluate validity, whether during original examination, or in reexamination or IPR. Errors may arise due to misinterpretation of the art, misleading arguments presented by the patent owner, or other circumstances. Barring subsequent challenges even where such error occurs hardly results in fairness and eliminates the system’s ability to correct those mistakes.
In short, the new rules are hardly fair. Once any party has tried and failed—no matter the reason for failure—the patent effectively gains enhanced immunity from further IPR scrutiny. Patent defendants are once again placed in the box they were in before Congress provided the IPR as an efficient and effective means to challenge validity.
Quiet Title Versus Patent Quality?
The USPTO claims that by limiting repeat challenges, it aims to restore “quiet title” and enhance reliability in patent grants. Yet, this comes at the cost of potentially allowing questionable patents to survive without sufficient opportunity for review. A strong patent system depends not just on quiet title, but on the ongoing opportunity to correct errors, especially when substantive arguments were never fully aired.
The proposed “one and done” regime’s insistence that a second challenge is almost never warranted may comfort patent owners and reduce APJ workloads, but it risks harming public confidence in the system. Especially for non-parties to the first action, there is little justice in being bound by a proceeding over which they had no control.
This raises difficult questions: Is the USPTO’s primary motive truly efficiency and fairness, or is it institutional fatigue? The agency has been criticized (sometimes unfairly) for improper examination, poor identification of prior art, and the issuance of “bad patents.” The USPTO is resource constrained and examiners are given limited time to search for and apply the best art in what is a very complex and difficult process. Recognizing that such challenges can lead to mistakes, Congress established the IPR process as a mechanism to correct errors that inevitably arise in the complex examination and post-grant-review processes. The proposed rules, however, close the door on further correction once a single proceeding (even a flawed one) is completed.
Shifting, Not Solving, the Efficiency Dilemma
The USPTO frames these proposed rules as a solution to enhance efficiency within the patent system. However, by drastically curtailing access to IPR review after a single challenge, the USPTO is not eradicating inefficiency—it is simply shifting the burden back to district courts. Rather than streamlining the overall process, the new rules risk funneling all subsequent validity disputes into district court litigation, which is universally recognized as costlier, slower, and more procedurally complex than PTAB proceedings. This would increase the load on federal courts, increase litigation expenses for all parties involved, prolong the resolution of patent validity questions, and embolden patent assertion entities.
In effect, the USPTO would make its own operations smoother, but at the expense of the broader system. By closing the door to additional IPR review, the USPTO isn't eliminating duplicative litigation; it is merely redirecting it, leaving innovators, businesses, and the courts to absorb the complications and expenses that follow.
Where There is a System, it will be Gamed
There is a risk that serial plaintiffs and NPEs will exploit the new rules to produce outcomes that are contrary to the intent of the IPR system. For example, consider the following scenario, which could play out under these rules. A patent owner files suit against a low-resourced and inexperienced defendant in a forum like the Western District of Texas, where courts routinely set trial dates as early as 18 months after filing. By declining to settle, the plaintiff can ensure that the trial date remains on calendar, triggering and maintaining the parallel litigation bar.
Subsequently, when the plaintiff asserts those same patents against major industry players, those better-resourced, more experienced defendants could be barred from initiating IPRs because the initial trial is likely to occur before any IPR process could reach a final decision. As a result, only the first, limited-resource defendant has the opportunity to pursue PTAB review. All subsequent defendants could be foreclosed from seeking IPR relief, regardless of the merits of their invalidity defenses. This dynamic is especially concerning where the initial defendant is unable to fully develop arguments or present the best prior art, effectively binding all future litigants to a single, potentially inadequate and flawed validity challenge.
Rather than streamlining the review of patent quality, these rules risk enabling the protection of low-quality patents, undermining the original purpose of IPR as an effective safeguard against improperly granted claims.
Where Do We Go from Here?
Most would agree that there are merits to having practical, common-sense limits on serial IPR challenges. But the USPTO must strike a truer balance in achieving that objective. The proposed rules threaten to virtually eliminate the opportunity for nuanced judgment or discretionary decision-making in the institution of IPRs, substituting rigid mandates for the panel’s sound evaluation of individual case circumstances.
This rigid framework prioritizes administrative efficiency over robust scrutiny. At minimum, the rules should allow for renewed IPR challenges where there is material new art or evidence, or where errors or other deficiencies arose or occurred in the prior challenge.
If the goal is to ensure only “quality” patents survive, mechanisms for correcting bad grants—even after an imperfect challenge—must remain robust.
Nothing is set in stone. The application and impact of these proposed rules is subject to ongoing developments, including future court decisions, PTAB precedent, and potential changes in the final regulatory text. Parties should watch for updates and consult qualified counsel to assess how evolving law and agency guidance may affect their rights and strategies.