Key Points

• DNJ grants stay pending ex parte reexamination: The court stayed patent litigation while all asserted patents undergo USPTO ex parte reexamination, reflecting the growing role of EPRs in stay motions.
• EPR can drive stays despite no estoppel: Although ex parte reexamination is non‑adversarial and lacks IPR‑style estoppel, claim cancellation or amendment can moot or materially narrow district court litigation.
• Issue simplification carries the most weight: Applying DNJ’s three‑factor test, the court emphasized that potential simplification of patent claims is the dominant factor in deciding stays pending USPTO reexamination.

Stay Pending EPR?

Ex parte reexamination (EPR) filings have nearly tripled in recent years — rising from 163 in fiscal year 2019 to 491 in fiscal year 2025 — even as inter partes review (IPR) petitions and institution rates have declined, and this trend is impacting patent litigation.

Recognizing that federal courts will increasingly confront stay motions tied to these proceedings, Chief Judge Renée Marie Bumb of the District of New Jersey carefully reviewed the steps of EPR proceedings before evaluating whether a stay was warranted.

In a 27-page opinion in Jiaxing Super Lighting Electric Appliance Co., Ltd. et al. v. All Star Lighting Supplies, Inc., et al., the Court issued a stay, granted with ongoing judicial supervision designed to address whether a stay remained appropriate as the EPR proceeded.

Procedural Posture

In June 2025, plaintiffs Jiaxing Super Lighting Electric Appliance, Co., Ltd. (Super Lighting), and Obert, Inc. (Obert) filed suit against All Star Lighting Supplies, Inc. d/b/a Luxrite (Luxrite) and Xiamen Pvtech Corporation, Ltd. (Pvtech).

Pvtech was served via the Hague convention in December 2025, and it moved to stay the proceedings in January 2026 pending EPR and filed one request for EPR of one asserted patent. While Pvtech’s motion was pending, it submitted additional EPR requests, which were ultimately granted such that all nine asserted patents were to be reexamined.

Motion to Stay Factors

Motions to stay proceedings are “committed to a district court’s sound discretion.” Although “there is no per se rule governing motions to stay in patent cases,” the Court analyzed Pvtech’s request to stay pending EPR under three factors previously recognized in the DNJ:

1. whether a stay would unduly prejudice or present a clear tactical disadvantage to the non-moving party
2. whether a stay will simplify the issues and the trial of the case, and
3. whether discovery is complete and a trial date has been set.

The party requesting the stay bears the burden.

Ex Parte Reexamination

Before assessing the factors, the Court provided background on EPR proceedings given the recent increase and differences in EPR versus other patent review proceedings. By statute, the EPR process allows “any person at any time [to] file a request for reexamination with the [USPTO] on the basis of any prior art.” 35 U.S.C. § 302.

There are three possible outcomes for claims undergoing reexamination:

• cancellation as unpatentable
• confirmed as originally written, or
• modified

Critically, a patent claim cancelled or modified during EPR to “cure invalidity … renders any pending infringement litigation before a District Court moot, such that the cancellation or amendment of claims binds any parallel, pending litigation in the District Court.”

Differences from IPR

The Court identified and analyzed three primary differences between EPR and IPR.

First, EPR is “typically non-adversarial,” with limited opportunity for a third-party to participate in initiated reexamination proceedings.

Second, EPR lacks the statutory estoppel associated with IPRs. By statute, if an IPR petition results in a final written decision, the petitioner “may not assert” in district court litigation “that the claim is invalid on any ground that the petitioner raised or reasonably could have raised” during the IPR. 35 U.S.C. § 315(e)(2). The Court noted the absence of a corresponding statutory estoppel provision for EPR, although it can still “narrow the issues” before a district court through the binding effect of cancellation or amendment of any claims.

Third, EPR proceedings “have historically taken longer to resolve” than IPRs. By statute, IPRs must progress under a strict timeline, with completion of an instituted IPR within 18 months of initial filing. In contrast, EPR is not subject to any such statutory limitations. The Court noted recent USPTO statistics from the parties that “the average pendency of an ex parte reexamination is 25.1 months.”

Factor One: Will a Stay Simplify the Issues?

Whether a stay would simplify the issues and trial of the case is the factor that “weighs the most,” the Court noted. An EPR may simplify the issues as “the USPTO need not reject all of the asserted claims to justify the imposition of a stay here as the case will be simplified even if only some of the claims are canceled.”

The Court held that this factor weighed in favor of a stay. All nine asserted patents were undergoing EPR. The Court noted USPTO statistics provided by Pvtech that “nearly 80% of claims granted for review are either cancelled outright or otherwise amended” by the USPTO. Based on this data, the Court “agree[d] that simplification of some kind will occur by reexamination” because the cancellation and amendment rates made it “more likely that the vast majority of Plaintiffs’ pending infringement claims could be mooted in this case.”

The Court rejected plaintiffs argument that any potential simplification would be speculative, particularly as no statutory estoppel would prevent them from reasserting any failed invalidity arguments before the Court. The Court noted that although plaintiffs could still raise failed invalidity arguments, “the USPTO’s historical data show that this risk of duplication is likely limited to the roughly 22% of claims ultimately confirmed by reexamination,” simplifying the case.

For the remaining claims, “the Court will have the benefit of the PTO’s expertise and views on the prior art, which can help focus and streamline the Court’s review of issues surrounding that art later in this litigation.” The Court cited precedent from the District of Delaware that “even if the PTO were to ultimately confirm all of the claims, the court would likely benefit from the expert analysis the PTO conducts, thus further simplifying issues before the court.” The Court further noted that a “stay will also avoid the complicating peril of this Court issuing inconsistent decisions.”

Factor Two: Undue Prejudice or Clear Tactical Disadvantage to Plaintiffs

The Court began its analysis of the second factor by noting “delay inherent to the reexamination process does not constitute, by itself, undue prejudice.”

The Court analyzed “a number of subfactors for this prong, including, the timing of the request for reexamination, the timing of the request for [a] stay, the status of the reexamination proceedings and the relationship of the parties.”

Timing of Pvtech’s Requests
The Court found that the timing of Pvtech’s requests for reexamination weighed against a stay here. The Court noted that “while it is Plaintiffs’ burden to timely effectuate service of the complaint, the Court does find it concerning that Luxrite’s counsel refused to waive service on Pvtech’s behalf and moved to stay the entire proceeding pending service, but then immediately after Plaintiffs effectuated service via the Hague Convention, counsel took up Pvtech’s representation…Given this conduct, Plaintiffs’ point is a legitimate one.”

Timing of Motion and Status of EPR Proceedings
The Court considered Plaintiffs’ primary argument under these sub-factors that the risk of undue prejudice is heightened by the 25-month average time to complete EPR proceedings, noting that the potential lengthy time to resolve proceedings could result in prejudice.

The Court found that “this factor remains neutral at present but could change as the reexamination proceeds.” Importantly, the Court noted it “will monitor developments before the USPTO and re-evaluate the appropriateness of a stay depending on the pace and efficiency of that parallel review. In particular, the Court is keen to understand how actively Super Lighting participates in the reexamination in defense of its patents. After all, if a patent owner is unwilling to defend its patents, it can hardly complain that this Court should have afforded it the opportunity to prosecute them.”

Whether Relationship Between Parties Favors Stay
Although courts are “generally reluctant” to grant a stay where the parties are direct competitors on the rationale that a stay would likely cause the non-movant to lose substantial profits and goodwill on the market, the Court noted that being direct competitors does not necessarily result in undue prejudice for a party.

The Court initially noted “the risk of undue prejudice against Obert, as a direct competitor to Pvtech, is heightened.” However, the presence of other competitors in the market tempered the undue prejudice claims, “which causes some pause in affording this factor too much weight.” The Court further noted that “Plaintiffs have not shown any actual market loss that would result from a stay, [which] also causes a similar pause,” contrasting cases where parties submitted declarations with those that did not.

After considering these subfactors, the Court found “that this second factor concerning undue prejudice and tactical disadvantage weighs slightly against granting the stay.”

Factor Three: Whether Discovery is Complete or a Trial Date is Set

The Court found this factor weighed in favor of a stay, as the case is in the very early stages. The Court noted that although “both parties had some hand in the delay to date, the relevant inquiry under this factor is how much work remains to be done in this case. The fact is that this litigation remains in its earliest stages: Plaintiffs filed suit in June 2025, the Court set the initial case management schedule in February 2026, and the parties are operating under a February 27, 2027 fact discovery deadline, without a trial date.”

Granting the Stay with Supervision

The Court held that a stay was appropriate under the present circumstances. However, the Court “remains cognizant that the risk of undue prejudice is likely to increase according to the pace of the reexamination proceedings and the action — or inaction — of the parties.”

Thus, the Court indicated that its accompanying order would require updates from the parties, including the status of the EPRs and whether Super Lighting participates. Based upon these updates, the Court will reevaluate the appropriateness of continuing the stay.

Paul W. Kalish and Jonathan J. Madara are members of the IP Litigation team in Fox Rothschild’s Princeton, NJ office and write about patent litigation decisions in the District of New Jersey. Contact Paul at pkalish@foxrothschild.com or 609.895.6751 and Jonathan at jmadara@foxrothschild.com or 609.844.7428.

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