EPR Academy, Part 5 of 6: Special Considerations for Third-Party Requesters

Introduction & Recap

The first four installments of Finnegan’s EPR Academy series introduced ex parte reexamination (“EPR”), walked through the process from request to reexamination certificate, detailed the EPR appeals process, and compared EPR to IPR, PGR, and reissue. A mid-series Alert also covered the USPTO’s new patent-owner pre-order paper procedure. If you have not read them, be sure to give them a look.

With this fifth installment, we turn from mechanics to strategy, focusing on the special considerations that shape EPR practice for a third-party requester—the accused infringer, competitor, or other challenger who uses EPR to test a patent’s validity. The sixth and final installment will address these special considerations from the patent owner’s perspective.

The Third-Party Requester’s Defining Constraint: Limited Participation

One of the most important strategic features of EPR for a third-party requester is also one of its greatest limitations: the requester’s role is brief. A third-party requester may file the request and, if the patent owner elects to file a statement after reexamination is ordered, may file a single reply within two months of service of that statement.^[1] That reply is not confined to the subject matter of the patent owner’s statement and may even introduce additional prior art patents and printed publications.^[2] But if the patent owner files no statement, the requester has no right to reply at all.^[3] After the reply window closes, the proceeding becomes purely ex parte, and the third party may no longer participate.^[4]

This structure has a decisive practical consequence: the requester must treat the request itself—and, where available, the reply—as its only opportunity to shape the outcome. Because the requester cannot respond to the examiner’s office actions, cannot rebut the patent owner’s amendments or arguments during examination, and cannot steer the examiner after the reply, it is good practice to build the request to stand on its own. That means anticipating the patent owner’s most likely amendments and framing prior-art grounds that remain potent against foreseeable narrowing. It also means presenting both primary and backup grounds and, in most cases, supporting the request with an expert declaration, which can materially strengthen the showing.^[5]

The requester does remain on the distribution list: the USPTO mails the third-party requester a copy of each office action in the proceeding.^[6] That access is informational only, however; it confers no right to respond. And critically, only the patent owner may appeal an adverse decision—third-party requesters cannot appeal or participate in an EPR appeal.^[7] If the examiner confirms the challenged claims, the requester has no recourse within the proceeding itself. The request is, functionally, the requester’s best and often last chance.

Anonymity and the Real-Party-in-Interest Advantage

A distinct advantage of EPR over IPR and PGR is confidentiality of the true challenger. “Any person” may request EPR, and among the persons the USPTO expressly contemplates are “attorneys without identification of their real client in interest.”^[8] While the name of the individual or firm that signs and files the request is not kept confidential, a request filed through counsel need not disclose the real party in interest behind it.^[9] By contrast, an IPR petition must identify all real parties in interest.^[10]

For a litigation-minded requester, that anonymity is often the reason to choose EPR over IPR. A supplier can challenge a customer’s patent without naming itself, and a defendant can test validity without previewing the art it intends to use in court. Those are strategic benefits, not doctrinal ones, but they frequently drive the forum choice.

That advantage now comes with a new condition. In February 2026, the USPTO updated the certification expected of anonymous requesters whose requests target claims previously challenged in an IPR or PGR. Where at least one challenged claim was the subject of an IPR or PGR proceeding that resulted in a final written decision, an anonymous requester should affirmatively state that the real party in interest is not the petitioner—or a real party in interest or privy of the petitioner—in that prior proceeding.^[11] In effect, the USPTO has paired continued anonymity with a heightened, estoppel-focused certification, closing a potential avenue for an estopped party to relitigate through an anonymous EPR.

Estoppel: What EPR Does and Does Not Trigger

Estoppel is where EPR offers one of its most underappreciated advantages to third-party requesters. EPR carries no statutory estoppel of its own. Unlike IPR and PGR, which prevent a petitioner (and its real parties in interest and privies) from later asserting invalidity grounds that were raised or reasonably could have been raised,^[12] the EPR statute imposes no comparable bar on an unsuccessful requester. A requester whose EPR does not succeed generally remains free to press the same prior-art invalidity arguments in district court or at the International Trade Commission. For an accused infringer weighing forums, that preservation of litigation defenses can be a valuable consideration.

The estoppel that matters in EPR arises from prior IPRs or PGRs. A party subject to a final written decision in an IPR or PGR cannot file a subsequent EPR on grounds it raised or reasonably could have raised, which is why every EPR request must certify that the estoppel provisions of 35 U.S.C. §§ 315(e)(1) and 325(e)(1) do not apply.^[13]

The sequencing implications of estoppel are significant. A requester that wants to keep its full arsenal of invalidity defenses available in litigation may prefer EPR precisely because it does not spend those grounds. EPR is also available when IPR is not, such as after the one-year window to petition for IPR following service of an infringement complaint has closed.^[14] Choosing EPR early, or in lieu of an IPR, can therefore preserve options that an IPR final written decision would foreclose.

Navigating the Rising Risk of § 325(d) Discretionary Denials

Historically, the high grant rate for EPR requests made ordering reexamination close to a sure bet. That, however, is changing lately, as the USPTO has begun applying its discretionary authority under 35 U.S.C. § 325(d) to deny EPR requests, not just IPR and PGR petitions as has historically been the case.^[15] Under that authority, the Office may decline to order reexamination where the same or substantially the same prior art or arguments were previously presented to the Office.

The Patent Trial and Appeal Board’s (“Board”) now-familiar § 325(d) framework informs how requesters should build around this risk. The two-part inquiry asks whether the same or substantially the same art or arguments were previously before the Office and, if so, whether the requester has shown that the Office materially erred in its prior evaluation.^[16] The non-exclusive factors the Board weighs—such as the similarity of the asserted art to what the examiner already considered and the extent to which the art was evaluated—come from the Board’s precedent.^[17] The practical lesson for a requester here is to start the EPR process with an investigation into the prosecution of the patent at issue and any challenges made against that patent family to identify the art and arguments that were previously raised before the Office. From there, a requester should strive to lead with genuinely new prior art, to explain expressly why that art raises a substantial new question of patentability (“SNQP”) the Office has not already resolved, and, where relying on previously cited art is unavoidable, to demonstrate the Office’s material error in its earlier treatment.

The New Pre-Order Paper: Anticipating Early Patent-Owner Advocacy

The USPTO’s new pre-order paper procedure changes the threshold dynamic in third-party requested EPRs. For requests filed on or after April 5, 2026, a patent owner may file a pre-order paper—thirty pages or fewer, within thirty days of being served with the request—rebutting the requester’s assertion that the request raises an SNQP.^[18] For the first time, a patent owner can argue against ordering before the examiner makes the SNQP determination and can potentially prevent reexamination from being ordered at all.

For requesters, this is a meaningful shift. The requester ordinarily has no right to respond to the pre-order paper. Only in limited circumstances—where the patent owner’s paper allegedly misrepresents fact or law or otherwise improperly impedes the SNQP determination—may a requester seek leave to file a responsive paper, and even then the response is capped at ten pages, due within fifteen non-extendable days of service, and must be accompanied by a grantable petition and fee.^[19] The strategic response is twofold. First, draft the request to be self-proving on SNQP, with claim charts and, where appropriate, an expert declaration that make the substantial new question difficult to rebut. Second, monitor for the patent owner’s pre-order paper and be prepared to seek leave to respond promptly if it crosses the line into misrepresentation.

Leveraging EPR in Parallel Litigation

EPR’s procedural features make it a versatile companion to litigation for a third-party requester.

• Timing and speed. Because EPR may be requested at any time during a patent’s period of enforceability, it is not subject to the one-year bar that constrains IPR petitions after service of an infringement complaint. And EPR proceedings are conducted with statutory “special dispatch,” taking priority over most other Office matters, with only reexaminations and reissues tied to active litigation receiving higher priority. ^[20] For a defendant seeking a relatively quick validity determination, that expedited handling is an asset.
• Claim construction. For unexpired patents, examiners in EPR apply the broadest reasonable interpretation standard, which tends to produce broader constructions and can make prior art easier to read onto the claims; IPR and EPRs involving expired patents instead apply the Phillips standard used in district court.^[21] A requester challenging an unexpired patent may find the same reference more effective in EPR than in litigation for exactly this reason.
• Building a useful prosecution record. Reexamination can generate statements by the patent owner regarding claim scope, the meaning of claim terms, and distinctions over the prior art. Those statements become part of the prosecution history and may prove significant in later litigation, including claim-construction proceedings. A requester should therefore think strategically about the prior art it selects. In some circumstances, prior art that closely resembles the accused product may prompt the patent owner to draw distinctions that are not only relevant to patentability, but also informative for later infringement analyses.
• Litigation stays. A defendant may ask a district court to stay litigation pending EPR. Courts weigh undue prejudice, potential for simplification of the issues, and the stage of the case when evaluating such a request. Those factors favor a stay when reexamination is already ordered, the challenged claims overlap the claims asserted in court, and the district court case is still in early stages. Statutory special dispatch reinforces that showing: the Office must conduct reexaminations of patents involved in litigation with priority over cases without related litigation. The 2026 Jiaxing case is a concrete illustration. The requester filed EPR requests against all ten patents asserted in the District of New Jersey; the USPTO ordered reexamination on all ten, covering every asserted claim; and on April 24, 2026, Chief Judge Bumb stayed the litigation, citing the early stage of the case and the overlap between the ordered reexaminations and the patents in suit.^[22] Outcomes still vary by judge and posture—a late-stage motion or a request that has not yet been ordered are harder sells—but an ordered EPR aimed at the asserted claims is a legitimate and increasingly effective basis for a stay. That is not to say that a defendant should wait to move for a stay until after reexamination has been ordered. Rather, in many cases, it is best to file the motion to stay as soon as possible after filing the EPR request and notify the court if/when reexamination is ordered.
• Intervening rights. A frequently overlooked upside for accused infringers is intervening rights. If reexamination results in amended or new claims, those claims carry the same intervening-rights consequences that § 252 provides for reissued patents.^[23] Absolute intervening rights can eliminate liability for products made or used before the reexamination certificate issues, and equitable intervening rights may permit continued activity thereafter where the infringer made substantial preparations beforehand. Importantly, the Federal Circuit has held that intervening rights arise only where the text of a claim is actually amended or new.^[24] A requester should therefore recognize that forcing the patent owner to amend can be as valuable as securing cancellation. Relatedly, cancellation of claims in reexamination can extinguish even a pending infringement judgment that has not yet become final.^[25]

Managing the Downside Risk of a Strengthened Patent

EPR is not without risk for the challenger, and a candid strategic assessment should weigh the possibility that the patent emerges stronger. Claims that survive reexamination have been confirmed over the very art the requester raised, which can make them more difficult to attack later and may bolster their perceived strength before a jury. This is a judgment call rather than a certainty, but it is a real consideration when the prior art is less than compelling.

The requester should also account for its lack of control once the proceeding is underway. Unlike an IPR, which the parties can jointly settle and terminate, an ordered EPR proceeds to conclusion regardless of the requester’s wishes; the third party cannot settle or withdraw the reexamination once it becomes ex parte. A requester that files should be prepared to live with the result. Finally, requesters should remember that the USPTO has cautioned that reexamination is not a venue for “litigation tactics.”^[26] In practice, that means do not file a request whose only purpose is delay, and do not use the reply to add art that has no bearing on the substantial new question of patentability already ordered.

Final Thoughts

For third-party requesters, EPR is a tool of front-loaded advocacy. Its advantages are considerable: broad availability, anonymity, the absence of requester-side estoppel, favorable claim construction, expedited handling, and the prospect of intervening rights. Those advantages have to be captured in the request itself, because the requester’s window closes early and does not reopen.

Before filing, investigate the prosecution of the patent and any challenges to the family, and lead with art and arguments that were not already before the Office. Chart the amendments the patent owner is most likely to make, and frame grounds that still read on those narrower claims. Where the substantial new question of patentability is open to dispute, support it with claim charts and an expert declaration. Then calendar two dates: the patent owner’s thirty days to file a pre-order paper, and, if that paper misstates fact or law, the fifteen non-extendable days to seek leave to respond. After the reply window closes, none of that can be added.

The expanding use of § 325(d) discretionary denials and the patent-owner pre-order paper raise the premium on that work. A complete, persuasive, and genuinely new request is now what separates an EPR that is ordered from one that is not.

Stay tuned for the sixth and final EPR Academy installment, where we examine these special considerations from the patent owner’s perspective.

Endnotes

[1] 37 C.F.R. § 1.535; MPEP § 2251 (9th ed. Rev. Jan. 2024).

[2] MPEP § 2251 (9th ed. Rev. Jan. 2024).

[3] MPEP § 2251 (9th ed. Rev. Jan. 2024).

[4] MPEP § 2251 (9th ed. Rev. Jan. 2024).

[5] MPEP § 2214 (9th ed. Rev. Jan. 2024).

[6] MPEP § 2264 (9th ed. Rev. Jan. 2024).

[7] 35 U.S.C. § 306; MPEP § 2273 (9th ed. Rev. Jan. 2024).

[8] 35 U.S.C. § 302; MPEP § 2212 (9th ed. Rev. Jan. 2024).

[9] MPEP § 2212 (9th ed. Rev. Jan. 2024); see MPEP § 2210 (9th ed. Rev. Jan. 2024).

[10] 35 U.S.C. § 312(a)(2).

[11] U.S. Pat. & Trademark Off., Update Regarding the Filing of Anonymous Requests for Ex Parte Reexamination (Feb. 6, 2026).

[12] 35 U.S.C. §§ 315(e)(1), 325(e)(1).

[13] 37 C.F.R. § 1.510(a); 37 C.F.R. § 1.510(b)(6).

[14] 35 U.S.C. § 315(b); see MPEP § 2211 (9th ed. Rev. Jan. 2024).

[15] 35 U.S.C. § 325(d); see, e.g., In re Patent No. 8,810,458, No. 90/015,984, Order Denying Request for Ex Parte Reexamination (U.S.P.T.O Central Reexam. Unit May 22, 2026).

[16] Advanced Bionics, LLC v. MED-EL Elektromedizinische Geräte GmbH, IPR2019-01469, Paper 6 (P.T.A.B. Feb. 13, 2020) (precedential).

[17] Becton, Dickinson & Co. v. B. Braun Melsungen AG, IPR2017-01586, Paper 8 (P.T.A.B. Dec. 15, 2017) (precedential).

[18] Pre-Order Procedure Regarding Substantial New Question Determination in Ex Parte Reexamination Proceedings, 1545 Off. Gaz. Pat. & Trademark Off. 217, 217–18 (Apr. 28, 2026).

[19] Pre-Order Procedure Regarding Substantial New Question Determination in Ex Parte Reexamination Proceedings, 1545 Off. Gaz. Pat. & Trademark Off. 217, 218 (Apr. 28, 2026).

[20] 35 U.S.C. § 305; MPEP § 2261 (9th ed. Rev. Jan. 2024).

[21] In re CSB-Sys. Int’l, Inc., 832 F.3d 1335, 1337 (Fed. Cir. 2016).

[22] Jiaxing Super Lighting Elec. Appliance Co. v. All Star Lighting Supplies, Inc., No. 1:25-cv-12390 (D.N.J. Apr. 24, 2026) (Bumb, C.J.) (granting stay pending ex parte reexamination); see also Finnegan, Pvtech Secures Stay of New Jersey District Court Litigation Following USPTO Institution of All 10 Ex Parte Reexamination Requests (Apr. 28, 2026).

[23] 35 U.S.C. § 307(b); 35 U.S.C. § 252; MPEP § 2293 (9th ed. Rev. Jan. 2024).

[24] Marine Polymer Techs., Inc. v. HemCon, Inc., 672 F.3d 1350, 1362 (Fed. Cir. 2012) (en banc).

[25] Fresenius USA, Inc. v. Baxter Int’l, Inc., 721 F.3d 1330, 1344–45 (Fed. Cir. 2013).

[26] MPEP § 2209 (9th ed. Rev. Jan. 2024).