Ex Parte Reexamination, American Invents Act, and International Trade Commission Proceedings—A Compare and Contrast Primer

Senior Manager of Business Development and Analytics, Patrick Murray, and Manager of Research & Knowledge Services, Chad Gilman, contributed to this article.

Introduction

The general landscape of patent litigation has undergone significant operational shifts in light of policy changes implemented at the U.S. Patent and Trademark Office (USPTO) since 2025. Nowhere is this more prominent than in America Invents Act (AIA) proceedings adjudicated at the Patent Trial and Appeal Board (PTAB).

Since March 2025, inter partes review (IPR) and post-grant review (PGR) proceedings under the AIA have experienced an unprecedented drop in institution rates, which have led to a sharp drop in filings. Both occurred after the USPTO Interim and then Director implemented numerous new policies and procedures that appeared to limit when patents could be challenged in AIA reviews. The policy changes included, as just a few examples, implementation of the Director handling all aspects of decisions on institution (discretionary denial considerations and merits), a heightened deference to patent owners’ “settled expectations” based on the age of a patent, and stricter requirements for how a petitioner may present claim construction positions with respect to other forums and how they identify real parties in interest.

Nonetheless, IPRs and PGRs remain viable and important options, especially as the frequency and speed of new changes appear to be settling a bit recently. In fact, in recent months, we have seen an uptick in AIA institution rates, i.e., ~60% since June 2026 through September 9, 2026, which is up from earlier months over the last year being less than ~30-40%. In fact, even more recently, from August 1 through September 9, 2026, the Director has “referred” about 74% of AIA petitions (29) for consideration on the merits (e.g., reasonable likelihood of success), and discretionarily denied about 26% (10).

In view of the numerous policy changes impacting AIA reviews, however, many companies and businesses have started considering other options. Invalidity challenges at the USPTO can be important when defending allegations of patent infringement and addressing requests for high damage awards or settlement amounts, or when simply considering freedom to operate. Beyond IPRs and PGRs, another option at the USPTO is ex parte reexamination (EPR) at the Central Reexamination Unit (CRU). Over the last year, requests for EPR have dramatically increased as AIA petition filings have gone down. In fact, since October 2025, challengers have filed more EPR requests than AIA petitions.

Beyond district court litigation, it also is important for practitioners to be familiar with another agency that adjudicates patent cases, i.e. the International Trade Commission (ITC). The ITC handles Section 337 (19 U.S.C. § 1337) investigations, which address unfair importation of products that infringe U.S. IP rights or engage in unfair methods of competition. Similar to complaints in district courts, ITC complaints alleging infringement can motivate a respondent to file an AIA petition or EPR request. While ITC investigations differ procedurally and operationally from district court litigation and USPTO proceedings in many ways, there are similarities and it is not uncommon to see multiple types of related cases going on concurrently. For example, it is not unusual for a party to file ITC and district court complaints on the same day, knowing the district court action will be stayed if the ITC institutes an investigation and the respondent files a timely motion for a stay in the district court.

This article compares the unique statutory, procedural, and strategic features of patent adjudication at two agencies, EPRs and AIA proceedings at the USPTO and Section 337 investigations at ITC, highlighting how practitioners can leverage the strengths and limitations of each forum, individually and in conjunction with parallel district court litigation, to advance their litigation and patent validity objectives.

Table 1: Recent Filing Trends and Institution Rates Across EPR, PTAB, and ITC Proceedings (through August 31, 2026)[1]

As shown above, institution rates for AIA reviews dropped from 68% in 2024 to less than 35% in 2026 overall as of the end of August (although there has been an increase in rates in recent months, as discussed above). After March 2025, the USPTO also experienced a notable drop in AIA petition filings, with IPR petitions falling by nearly 70% since 2024 (from about 1300 to about 400 projected for 2026). PGR petitions went up slightly from 41 in 2024 to 74 in 2025, and 31 so far in 2026. That said, PGR petitions have historically been in that general filing range (~30-80 per year) since well before 2024. In other words, it is not clear the new policies have had much of an impact on PGR filings. Meanwhile, requests for EPRs have dramatically increased—by more than double (if not triple, as projected for 2026) since 2024—at the same time AIA petition filings went down.  ITC investigation filing rates have not changed much.[4] And in stark contrast to AIA cases, institution/grant rates in both EPR and ITC proceedings both remain quite high at over 90% (and between 96% to 100% at the ITC).

As shown in Table 2 below, a significant percentage of EPRs, AIA proceedings, and ITC investigations overlap with parallel district court litigation, requiring practitioners to consider not only the advantages of each forum individually, but also how proceedings in one venue may affect outcomes in another.

Table 2: Incidence of Parallel District Court Litigation in EPR, PTAB, and ITC Proceedings

Of the three types of cases, the highest instance of parallel district court ligation occurs with AIA proceedings, where about 80%-85% of AIA cases have such parallel litigation, as seen consistently over the years. This high percentage is not surprising since being sued for infringement in district court is often what spurs defendants to take action in terms of defensive patent challenges, and AIA proceedings allow defendants/petitioners to participate throughout the proceeding. It is worth noting, however, that even before the many recent policy changes at the USPTO, defendants generally have been selective about when they file AIA petitions because less than 30% of district court cases have had co-pending AIA proceedings in past years.[6] Interestingly, about 60% of ITC proceedings have co-pending district court litigation, while EPRs appear to have the lowest at about 20% in 2025 (and in 2026 so far). Regardless, no matter what the forum, all parties should consider the pros and cons of co-pending litigation as part of their overall litigation strategy.

To assist practitioners in evaluating these considerations, Table 3 below compares key statutory, procedural, timing, and other features in the different proceedings.

Tables 3A-C: Comparative Overview of Key Procedural, Strategic, and Other Considerations in EPR, PTAB, and ITC Proceedings

Table 3A—At The Time of Filing

Table 3B—After a Case Is Filed

Table 3C—After an initial determination

Compare and Contrast of EPR, IPR, PGR, and ITC—what does the information tell us?

As seen above, EPR, IPR, PGR, and ITC proceedings have notable differences in terms of who can file, what issues can be addressed, costs involved, discovery allowed, remedies available, and potential impact on co-pending litigation. But they also have notable similarities. For example, parties may challenge the validity of patent claims in all four proceedings. That said, EPR and IPRs are limited to anticipation and obviousness challenges based on patents and printed publications, while petitioners in PGRs and respondents at the ITC may raise any validity grounds, just like in district court litigation. In other words, it is important to understand what validity challenges and remedies are available in what forum, and the impact of one proceeding over another.

EPRs, IPRs, PGRs, and ITC proceedings often have co-pending district court litigation. This is not surprising in relation to EPRs, IPRs, and PGRs, as the need for validity challenges may become apparent only after one has been sued or threatened with a lawsuit for alleged infringement. The relatively high number of co-pending district court cases in relation to all three of the other proceedings (EPR, AIA, and ITC) may be due to different strategic considerations, the different issues that may be addressed, and remedies available in the different forums.

Speed and Cost

Like EPR and AIA proceedings, ITC cases conclude relatively quickly compared to most district courts. That said, like district court litigation, ITC investigations can be quite expensive, while USPTO proceedings cost much less. The differences in costs are likely due to the number of issues and expansive discovery in play at both the ITC and district court. By contrast, EPRs allow no discovery, and AIA reviews allow only limited, tailored discovery, although it does include cross-examination (depositions) of witnesses presented. Because those proceedings take place at the USPTO, patent owners may amend claims in EPRs and AIA reviews (not at the ITC or in district court), although patent owners choose to do so only rarely in AIA cases as compared to EPRs.

Remedies—ITC is Different

Notably, beyond the usual remedy available at the ITC (exclusion order to stop infringing imports), adjudication of validity issues at the ITC has a different impact compared to other forums.  Specifically, unlike at the USPTO or in district court, a finding of invalidity at the ITC only impacts that particular investigation and whether the ITC will issue an exclusion order impacting importation by the respondent. The ITC cannot cancel claims it finds invalid. Thus, the validity of such claims may be adjudicated again at the USPTO or in district court, even between the same parties. Texas Instruments, Inc. v. Cypress Semiconductor Corp., 90 F.3d 1558, 1568-69 (Fed. Cir. 1996).

Third-Party and Patent Owner Participation—EPRs Are Different

It is also worth noting that while EPRs may cost the least of all four proceedings, they also provide requesters with effectively no authorized ability to participate after an EPR request is granted. After the CRU orders a reexamination, a patent owner is free to talk with Examiners through one or more interviews, raise new arguments, cite new evidence, and amend claims—just like regular patent prosecution. But a third-party requester has no statutory authority to interact with the office or respond in any meaningful way. This means, for example, a requester may not: provide comments on how an Examiner uses the request and prior art, question or depose any witness that provides testimony in a declaration, or appeal a decision by the CRU or PTAB that confirms original claims or finds new claims patentable at any point along the way.[23] In other words, less expensive is not always better from the perspective of a challenger. A full assessment and understanding of all options, including pros and cons and likelihood of success in each forum, are always important.

Other Considerations

Considerations also include the impact of one type of proceeding over another. For example, there is an interplay between AIA and ITC proceedings, especially in relation to new policies implemented by the USPTO Director in the last year. The ITC generally does not stay its cases pending outcomes in EPRs, AIA trials, or district courts, but the existence of an ITC case can lead to a discretionary denial of institution in AIA cases. By contrast, as a general matter, district courts often stay litigation pending an outcome in an EPR or AIA trial.[24] Finally, the Office in the past has stayed reexaminations filed in parallel with AIA cases to avoid inconsistent results.[25] For this and other reasons, both EPRs and AIA reviews are often in a good position to act as faster, more efficient, and cheaper alternatives to district court litigation or the ITC when validity is an important concern.

Conclusion

EPRs, AIA proceedings, and ITC investigations each offer distinct procedural, substantive, timing, and cost advantages that may make one forum more attractive than another depending on a party’s objectives. For example, EPRs may provide the most economic forum for requesters to challenge patents but they only allow very limited third-party participation. On the other hand, for patent owners, while EPRs may be expensive (although less so than other forums), they can be very beneficial for strengthening a patent through use of interviews and amendments that can modify issued claims and/or add new claims.

Like district court, the ITC presents a robust forum in which to litigate patents and allows a variety of validity challenges for respondents beyond those based on prior art. ITC investigations can be extremely expensive for both complainants and respondents, however. IPRs and PGRs have been the traditional favorites for patent challengers (who often have been sued for infringement) for a balanced approach in terms of cost and ability to participate. But AIA proceedings have become less popular as of late, due to the recent decrease in institution rates and uncertainty in the forums. This said, IPRs and PGRs remain viable and important options. Understanding the nuances of all options at the USPTO, ITC, and in district court remains crucially important for all parties when considering how to best address potential patent validity challenges.

[1] All “2026” numbers in Tables 1-3C are through August 31, 2026.

[2] Numbers relating to EPR and AIA proceedings were obtained from USPTO databases (e.g., P-TACTS), Docket Navigator, https://portal.unifiedpatents.com/exparte/search, as well as additional data kindly provided by Unified Patents.

[3] Numbers relating to ITC proceedings (filed as violation complaints) were obtained from Docket Navigator and https://ids.usitc.gov/; https://www.usitc.gov/intellectual_property/337_statistics_number_new_completed_and_active.htm.  Some instituted ITC cases in one year were filed the prior year.

[4] Many ITC practitioners thought after the March 2025 Federal Circuit decision in Lashify v. ITC, 130 F.4th 948, which broadened the scope of cognizable domestic industry economic investments (a requirement for complainants), there might be an increase in ITC complaints filed. The increase has yet to clearly materialize. But for 2026, there might be a slight upward trend because 43 complaints have been filed already so far.

[5] Information in Table 2 was calculated based on information from Docket Navigator and data provided by Unified Patents. The % of EPRs with co-pending district court cases was calculated from Unified Patents data and considered how many EPR requests were filed in 2025, and how many of those involved a patent at issue in a district court case that was pending in 2025.

[6] See, e.g., https://www.rpxcorp.com/data-byte/the-overlap-between-patents-asserted-in-district-court-and-challenged-at-the-ptab/, “The Overlap Between Patents Asserted in District Court and Challenged at the PTAB,” report by RPX Corp. (June 1, 2023).

[7] As also noted in Table 3C, a petitioner, or its real party in interest or privy, in an IPR or PGR of claims that result in a final written decision may not request a proceeding before the USPTO (i.e., EPR, IPR, or PGR) with respect to such claims on any ground the petitioner raised or reasonably could have raised during that IPR or PGR. 35 U.S.C. §§ 315(e)(1), 325(e)(1).

[8] The ITC addresses products imported into U.S. alleged to injure a domestic industry or violate U.S. IP rights. In addition to what is listed above, the ITC also addresses trademark/copyright infringement, trade secret misappropriation, and antitrust issues in imports.

[9] The Commission must determine whether to institute a Section 337 investigation within 30 days after a complaint is filed. 19 CFR § 210.10.

[10] Requester may do so through unauthorized petition practice but only allowed in rare circumstances.

[11] 35 U.S.C. § 326(a)(11); 35 U.S.C. § 316(a)(11).

[12] https://www.usitc.gov/intellectual_property/337_statistics_average_length_investigations.htm.

[13] https://www.uspto.gov/sites/default/files/documents/reexamination-op-stats.pdf (based on Q1-Q3 average).

[14] See, e.g., Garmin Int’l., Inc. v. Cuozzo Speed Techs. LLC, IPR2012-00001, Paper 26 (P.T.A.B. March 5, 2013) (precedential).

[15] 35 U.S.C. § 305.

[16] 35 U.S.C. §§ 316(d), 326(d); 37 C.F.R. §§ 42.121, 42.221.

[17] Patent owners file motions to amend in ~8% of instituted AIA reviews; https://www.uspto.gov/sites/default/files/documents/motion_to_amend_installment_9.pdf

[18] Times for PTAB or Director were obtained from USPTO databases, such as https://www.uspto.gov/sites/default/files/documents/Monthly_Appeal_Stats_September_2025.pdf; https://www.uspto.gov/sites/default/files/documents/appeal_stats_july2026.pdf; and Director Review

[19] Time between docketing and decision at the Federal Circuit.

[20] Time between initial determination an ALJ and final determination by the Commissioner.

[21] 35 U.S.C. §§ 315(e)(1),(2); 35 U.S.C. §§ 325(e)(1), (2)..

[22] Texas Instruments Inc. v. U.S. Int’l Trade Comm’n, 851 F.2d 342 (Fed. Cir. 1988) (finding that ITC determinations regarding patent issues should be given no collateral estoppel effect); Texas Instruments, Inc. v. Cypress Semiconductor Corp., 90 F.3d 1558, 1568-69 (Fed. Cir. 1996) (holding that issue preclusion cannot apply to an ITC determination).,

[23] As noted above, EPR requesters are limited to using unauthorized 37 C.F.R. §1.183 petition practice to insert themselves into the proceeding or filing a second, co-pending reexamination to ask for merger of the proceedings and place new arguments in front of the CRU.

[24] While district courts often consider stays pending USPTO proceedings, the Eastern District of Texas has historically been less likely than many courts to grant stays, particularly for EPRs. Longhorn HD LLC v. NetScout Systems, Inc., 2-20-cv-00349 (E.D. Tex. Jan. 6, 2022). For AIA proceedings such as IPRs, when the PTAB has not yet decided whether to institute review, courts in this jurisdiction have frequently denied motions to stay, even where IPR petitions challenging some of the asserted patents are already pending. Barkan Wireless IP Holdings, L.P. v. Samsung Elecs. Co., Ltd., No. 2:18-CV-00028, 2019 WL 8647996, at *2 (E.D. Tex. Mar. 15, 2019).

[25] Notice Regarding Options for Amendments by Patent Owner Through Reissue or Reexamination During a Pending AIA Trial Proceeding (April 2019), 84 FR 16654-16658, at https://www.uspto.gov/patents/ptab/notice-regarding-options-amendments.