From PCT Search to U.S. Fast Track: Using the Patent Prosecution Highway in a Section 371 National Stage

Executive Summary: A U.S. national-stage application under 35 U.S.C. § 371 may qualify for accelerated examination through the Patent Prosecution Highway, but an international search report citing only “A” references does not itself establish eligibility. The applicant must review the latest relevant PCT written opinion or international preliminary report and confirm that at least one claim received affirmative findings for novelty, inventive step, and industrial applicability; counsel must also evaluate any search limitations, lack-of-unity findings, or Box VIII observations and ensure that every pending U.S. claim sufficiently corresponds to positively assessed subject matter. When acceleration is sought before the ordinary 30-month commencement date, the PPH request must be coordinated with an effective request for early national-stage processing and satisfaction of the applicable § 371 requirements. PPH can provide substantial acceleration without a separate petition fee, but it does not constrain the U.S. examiner’s independent analysis or guarantee allowance. Its greatest value therefore arises when the PCT claims were drafted and prosecuted with the desired U.S. claim architecture in mind, allowing the applicant to obtain speed without sacrificing commercially important claim scope or statutory categories.

I.                   Introduction

A Patent Cooperation Treaty application returns an international search report citing only “A” references. No “X” document is identified as particularly relevant against a claim. No “Y” combination is identified as undermining inventive step. The applicant is preparing a U.S. national-stage entry under 35 U.S.C. § 371 and would like the application examined promptly. At first glance, the next step seems obvious: file a Patent Prosecution Highway request with the national-stage papers.

That conclusion may be right, but the reasoning is incomplete. An all-“A” international search report is not ordinarily the operative PPH work product. The critical document is the accompanying written opinion—or a later international preliminary examination work product—and the critical question is whether at least one claim received affirmative findings for novelty, inventive step, and industrial applicability. Even then, every claim presented for U.S. examination must sufficiently correspond to a positively assessed claim, and a § 371 applicant seeking commencement of processing before 30 months must coordinate the PPH request with an effective request for early national-stage processing.

The Patent Prosecution Highway is therefore best understood not as a reward automatically triggered by a clean search, but as a claim-alignment strategy. When planned during the international phase, it can produce accelerated U.S. examination without a PPH petition fee. When treated as a filing-day afterthought, it can force the applicant to choose between speed and the claim architecture it actually wants.

II.                What the PPH Does—and What It Does Not Do

The PPH is a work-sharing framework. An Office of Later Examination may advance an application out of turn when an Office of Earlier Examination, acting as a national or regional office or as an International Searching Authority or International Preliminary Examining Authority, has found at least one corresponding claim allowable or patentable. The USPTO participates in Global PPH and IP5 PPH arrangements and may rely on positive national, regional, or PCT work product from a participating office. Implementation of the Global and IP5 Patent Prosecution Highway (PPH) Pilot Programs with Participating Offices, 1400 Off. Gaz. Pat. Office 172, 172–74 (Mar. 18, 2014). The Global PPH pilot was later extended indefinitely, while the IP5 PPH pilot was further extended in 2026 through January 5, 2029. Continuation of the Global Patent Prosecution Highway (PPH) Pilot Program with Participating Offices, 1409 Off. Gaz. Pat. Office 298 (Dec. 30, 2014); Continuation of the IP5 Patent Prosecution Highway (PPH) Pilot Program with the IP5 Offices, 1543 Off. Gaz. Pat. Office 234 (Feb. 10, 2026).

At the USPTO, the request operates as a petition to make the application special under 37 C.F.R. § 1.102(a). No petition fee is required. Notice Regarding the Elimination of the Fee for Petitions To Make Special Filed Under the Patent Prosecution Highway (PPH) Programs, 75 Fed. Reg. 29,312, 29,312–13 (May 25, 2010). Effective January 1, 2026, the USPTO’s office-specific PPH target is an average of six months from completion of the PPH request to the first office action on the merits. That figure is an office-wide performance target, not an application-specific deadline. The USPTO separately reports average PPH first-action pendency of approximately 7.5 months and has adjusted docketing by technology area so that PPH first-action pendency in a particular technology is approximately half the corresponding non-PPH pendency. Applicants should therefore treat PPH as a substantial acceleration mechanism, not as a promise that a particular application will receive an action within six months. U.S. Patent & Trademark Off., Patent Prosecution Highway (PPH)—Fast Track Examination of Applications (last updated Dec. 31, 2025).

But PPH status is procedural, not substantive. The U.S. examiner conducts an independent examination under U.S. law and remains free to reject the claims under §§ 101, 102, 103, or 112. The USPTO expressly cautions that participation does not guarantee that the U.S. result will match the earlier office’s result. U.S. Patent & Trademark Off., General PPH: Frequently Asked Questions 10, Q.31 (May 3, 2023) [hereinafter USPTO PPH FAQs]. A favorable PCT opinion may accelerate the first U.S. examination, but it does not import the PCT authority’s claim construction, prior-art analysis, or view of patent-eligible subject matter.

That limitation is not a defect in the program. It explains what the applicant is buying with PPH: earlier attention and the potential benefit of reusable search work, not a presumption of patentability.

III.             The ISR and the Written Opinion Perform Different Jobs

The most common PCT-PPH mistake is to treat the international search report and the written opinion as interchangeable. They are not.

The international search report identifies documents located by the search authority and assigns relevance codes. The Written Opinion of the International Searching Authority addresses whether the claimed invention appears to be novel, to involve an inventive step, and to be industrially applicable, as well as whether the application complies with other PCT requirements reviewed by the authority. PCT Rule 43bis.1(a). Unless Chapter II examination produces a later report, the International Bureau ordinarily issues an International Preliminary Report on Patentability under Chapter I having the same substantive contents as the written opinion. PCT Rule 44bis.1(a).

For PPH purposes, that separation matters. The Global/IP5 requirements treat a claim as allowable or patentable when the ISA or IPEA has determined that the claim is novel, inventive, and industrially applicable. Implementation of Global and IP5 PPH Pilot Programs, 1400 Off. Gaz. Pat. Office at 173. The supporting work product is therefore the latest relevant written opinion or international preliminary report—not merely the list of references appearing in the ISR. Id. at 174.

The operative review should begin with Box V of the written opinion. Box V provides a claim-by-claim statement—typically “YES” or “NO”—for novelty, inventive step, and industrial applicability. World Intell. Prop. Org., PCT International Search and Preliminary Examination Guidelines ¶ 17.42 (Jan. 1, 2026) [hereinafter PCT ISPE Guidelines]. At least one claim must receive a positive assessment on all three criteria to supply the required PCT predicate.

If the WO/ISA is unfavorable but the objections appear curable, Chapter II may provide a second path. The applicant may file a demand, submit argument and appropriate amendments, and seek a favorable Written Opinion of the IPEA or International Preliminary Report on Patentability under Chapter II. The demand generally must be filed by the later of three months from transmittal of the ISR and WO/ISA or 22 months from the priority date. PCT Rule 54bis.1(a). A favorable later work product can then become the PPH basis.

Chapter II should not, however, be treated as a costless supplemental opportunity. Because the USPTO requires the latest PCT work product, a later WO/IPEA or Chapter II report becomes the work product supplied with the PPH request and may change, narrow, or eliminate the favorable predicate reflected in an earlier WO/ISA. USPTO PPH FAQs, supra, at 6, Q.10. When the WO/ISA already supplies the desired positive claim set, the applicant should therefore consider whether Chapter II is necessary before creating a later operative work product.

IV.            What an “A” Reference Really Means

An all-“A” search is still significant. Under the PCT Guidelines, an “X” document is particularly relevant because, taken alone, it may defeat novelty or, in light of common general knowledge, inventive step. A “Y” document is relevant because it may defeat inventive step when combined with one or more other “Y” documents. An “A” document, by contrast, represents state of the art that is not prejudicial to novelty or inventive step. PCT ISPE Guidelines, supra, ¶¶ 16.66–.69.

Thus, an ISR containing only “A” references generally indicates that the search authority did not identify an X or Y reference against the claims to which the A citations were assigned. It often points toward a favorable Box V assessment, but it is not a substitute for reading the opinion.

The written opinion may disclose problems that the ISR codes do not answer. Box III may state that no opinion was established for certain claims because the subject matter was excluded, the claims were insufficiently clear or supported to permit a meaningful opinion, or no international search was conducted for those claims. Id. ¶¶ 17.32–.37. Box IV may identify lack of unity and reveal that only the first invention, or only inventions for which additional search fees were paid, received a complete search. Id. ¶¶ 17.38–.41. Box VIII may contain significant observations concerning clarity or support even where Box V contains favorable prior-art findings. Id. ¶ 17.50.

Accordingly, the practitioner should ask four separate questions:

1. Which claims were actually searched?

2. Which claims received “YES” findings for all three Box V criteria?

3. Are those claims affected by a lack-of-unity determination or a limitation on the search?

4. Do Box VIII observations require explanation or amendment under the applicable PPH procedure, or foreshadow a U.S. § 112 issue even if formal PPH eligibility remains available?

Box VIII observations do not automatically negate a favorable Box V finding, but they may show that the positive assessment was qualified, incomplete, or based on claims presenting clarity or support concerns. The Global PPH explanatory materials call for the applicant to identify and explain which claims remain patentable or allowable when the relied-upon PCT work product contains Box VIII observations. Because the USPTO form has no separately labeled Box VIII field, counsel should consult the applicable matrix and office-specific guidance and include the explanation in the claim-correspondence submission or an accompanying paper as appropriate. Japan Patent Office, Explanatory Material of Global PPH Matrix 17–18 (last visited July 27, 2026). This approach distinguishes the formal positive-claim predicate from an explanation of the completeness and significance of the PCT review—and from the separate risk of a later U.S. § 112 rejection.

There is a related but distinct rule for an Extended European Search Report. The USPTO’s guidance states that an EPO Extended European Search Report containing only “A” references directed to a particular claim may treat that claim as allowable for PPH purposes. USPTO PPH FAQs, supra, at 7, Q.14. That EPO-specific guidance should not be generalized into a rule that every PCT ISR containing only A references, standing alone, establishes PPH eligibility. In the PCT setting, the written opinion remains the document that provides the affirmative patentability assessment.

V.               A Section 371 Application Can Use PPH

A U.S. national-stage application under § 371 is eligible for PPH. The request may be filed with the national-stage entry papers or later, so long as substantive examination has not begun. If the national-stage application number has not yet been assigned, the USPTO permits “filed herewith” or “TBD” on the request form. The filing date identified for the § 371 application is the international filing date. USPTO PPH FAQs, supra, at 7, Q.17; 35 U.S.C. § 363.

The timing rule is more forgiving than many applicants assume, but it is not entirely within the applicant’s control. A notice to file missing parts does not constitute substantive examination, and even a restriction requirement does not necessarily foreclose PPH if the examiner has not started the first action on the merits. USPTO PPH FAQs, supra, at 10, Q.30. But if substantive examination begins before the PPH request is granted—not merely before it is filed—the request will be denied. Id. Q.32. Filing the request with a complete national-stage package reduces that race.

Seeking commencement of national-stage processing before 30 months introduces a second timing issue. For international applications filed on or after September 16, 2012, submission of the documents and fees required by § 371(c)(1) and (2) within the prescribed period causes the application to enter the national stage. 37 C.F.R. § 1.491(b). Entry, however, is distinct from commencement of national-stage processing. Subject to § 371(f), the national stage ordinarily commences at the applicable 30-month deadline. 35 U.S.C. § 371(b); 37 C.F.R. § 1.491(a). The applicant may obtain earlier commencement by making an express § 371(f) request when the application is in order and the applicable § 371(c) requirements have been satisfied. 35 U.S.C. § 371(f); U.S. Patent & Trademark Off., Manual of Patent Examining Procedure § 1893, subsection “Commencement and Entry” (9th ed. Rev. 01.2024, Nov. 2024).

“Fulfillment” is a third concept: the national stage must have commenced and all applicable § 371 requirements must have been satisfied. 37 C.F.R. § 1.491(c).

The current PTO/SB/20GLBL form includes that express § 371(f) request. It also warns that processing will not commence before 30 months unless the applicant fulfills the listed requirements under § 371(c)(1), (2), and (4): payment of the basic national fee, provision of the international application and any required English translation, and submission of the inventor oath or declaration. U.S. Patent & Trademark Off., PTO/SB/20GLBL, Request for Participation in the Global/IP5 Patent Prosecution Highway Pilot Program in the USPTO 1 (rev. Feb. 2025).

Practice Rule—PPH Eligibility Is Not Early Processing. An inventor oath or declaration is not a supporting document required merely to file a PPH request. But when the applicant seeks commencement of § 371 processing before 30 months through the current PPH form, the form expressly conditions the § 371(f) request’s effectiveness on satisfying § 371(c)(1), (2), and (4)—including the oath or declaration. Other applicable national-stage requirements remain independently operative. USPTO PPH FAQs, supra, at 5, Q.8; PTO/SB/20GLBL, supra, at 1.

PPH status also does not expedite pre-examination processing. The application must first complete the applicable formalities and be ready for examination before examiner-led acceleration can have practical effect. USPTO PPH FAQs, supra, at 8, Q.23. Nor does a granted PPH petition, standing alone, cause national-stage processing to commence before 30 months. Without an effective § 371(f) request, an application may have special status on paper while processing waits until the 30-month deadline. U.S. Patent & Trademark Off., Patent Prosecution Highway, supra. PPH eligibility and early commencement must therefore be analyzed separately.

The filing date also matters administratively. A § 371 national-stage application retains the PCT international filing date; it does not receive a new filing date based on the day the national-stage papers arrive. 35 U.S.C. § 363; USPTO PPH FAQs, supra, at 7, Q.17. That is the date that belongs on the PPH form.

VI.            Claim Correspondence Is the Real Gatekeeper

The positive PCT claim opens the door, but claim correspondence determines whether the U.S. application can walk through it. Every claim pending in the U.S. application when PPH participation is requested must sufficiently correspond to one or more claims found allowable or patentable by the earlier office. Implementation of Global and IP5 PPH Pilot Programs, 1400 Off. Gaz. Pat. Office at 173.

The Global/IP5 notice provides two correspondence routes. First, accounting for claim-format differences, a U.S. claim may correspond if it has the same or similar substantive scope as a positively assessed claim. Id.

That route may permit an independent U.S. claim to correspond to a positively assessed PCT dependent claim after incorporating the dependent claim’s limitations, provided the resulting scope is substantively the same or similar. Id.

Second, when the applicant instead relies on the proposition that the U.S. claim is merely narrower than the particular positively assessed claim used as the comparator, the additional narrowing limitation must be presented in dependent form from a corresponding claim. Id.; USPTO PPH FAQs, supra, at 9, Q.27. “Narrower” is thus not a universal safe harbor, but neither is every U.S. independent claim containing more limitations than a PCT independent claim automatically ineligible.

New claim categories present a particularly common problem. If the favorable PCT work product contains only method claims, a newly presented U.S. apparatus claim does not sufficiently correspond merely because it recites components configured to perform similar steps. Likewise, the USPTO does not treat an allowed “use” claim as supporting a newly cast method claim for PPH correspondence. USPTO PPH FAQs, supra, at 9, Qs.28–29. The program is designed to reuse examination of corresponding claims, not to infer patentability across statutory categories.

Consider a PCT application containing twenty method claims, all receiving positive Box V findings. At national-stage entry, the applicant wants three independent claims: a method, a system, and a non-transitory computer-readable medium. The method claim may map directly. The system and medium claims may be fully supported by the disclosure and sensible under U.S. practice, but they were not the claims positively assessed by the ISA. Adding them to the § 371 claim set may make the PPH request defective because all pending claims—not merely one representative claim—must correspond.

Those choices need not be confined to a single application. Counsel may file the § 371 application with the aligned method claims and PPH request while pursuing U.S.-specific categories in parallel in a § 111(a) bypass continuation, potentially with Track One—or in a later continuation from the national stage. The parallel strategy costs more and may create obviousness-type double-patenting and portfolio-coordination issues, but it can preserve both near-term PPH acceleration and broader U.S. claim architecture. Alternatively, the applicant may present the category-diverse claim set in one application and forgo PPH, or pursue only a bypass continuation with Track One. The right answer depends on whether speed, breadth, cost, or portfolio architecture carries the greatest value.

This choice should be made before the PPH request is granted. Once PPH status is granted, amended and newly added claims must continue to correspond to allowable or patentable claims in the earlier application, and the applicant must provide the required certification. Implementation of Global and IP5 PPH Pilot Programs, 1400 Off. Gaz. Pat. Office at 175. The USPTO permits certain later rewriting when a dependent claim has been identified as allowable but objected to because it depends from a rejected claim, but that prosecution-specific exception is not a general license to introduce new claim architecture. USPTO PPH FAQs, supra, at 11, Qs.34–35.

VII.         When PPH Is the Right Strategy

PPH is especially attractive when the international claim set already reflects the desired U.S. claim strategy. In that setting, the applicant can use a positive PCT assessment to obtain earlier examination without paying a PPH petition fee and without preparing the pre-examination search and examination-support document historically associated with accelerated examination. The result may be particularly useful when the business needs an early U.S. patent for financing, licensing, enforcement planning, procurement, or continuation development.

PPH can also be uniquely useful at initial § 371 entry because Track One is not available at that stage. Original Track One prioritized examination under 37 C.F.R. § 1.102(e)(1) is limited to an original utility or plant nonprovisional application filed under § 111(a). A § 371 application can obtain Track One later with a qualifying request for continued examination, but not simply as part of the initial national-stage entry. U.S. Patent & Trademark Off., Prioritized Examination: Frequently Asked Questions 2, 7–8, Qs.2, 16–18 (rev. Sept. 2025) [hereinafter Prioritized Examination FAQs]. An applicant wanting immediate Track One treatment instead may consider a § 111(a) bypass continuation, but that choice carries its own filing, priority, translation, and prosecution considerations.

There are also reasons to decline PPH. The positive PCT claims may be materially narrower than the commercially important U.S. claims. The applicant may need system, medium, product, or method categories not included in the positive work product. Box III, IV, or VIII may reveal that the favorable result rests on an incomplete search or unresolved claim defect. Or the applicant may prefer additional time to refine the product, evaluate competitors, coordinate foreign prosecution, or build a continuation strategy.

Acceleration itself is not always neutral. Earlier examination compresses decisions about amendments, declarations, interviews, continuations, and appeal. Moreover, PPH status cannot simply be withdrawn after it is granted; it remains with the application, including through an RCE, although it does not automatically carry into a continuation. USPTO PPH FAQs, supra, at 9, Qs.24–26. Applicants should request PPH because earlier examination advances the portfolio strategy, not merely because the request is available and carries no separate PPH fee.

VIII.       PPH and Track One Solve Different Problems

PPH and Track One are sometimes described as interchangeable acceleration tools, but they serve different filing postures.

PPH requires a positive result from a participating office and corresponding claims. It imposes no separate USPTO petition fee and can be requested in a § 371 application before substantive examination begins. Its principal constraint is substantive correspondence to the claims already evaluated elsewhere.

Track One does not require favorable foreign or PCT work product and therefore provides greater freedom to present a U.S.-specific claim set. But it requires the prescribed fees, limits the application to no more than four independent claims, thirty total claims, and no multiple dependent claim, and—at original filing—is available only for an application filed under § 111(a). 37 C.F.R. § 1.102(e)(1). Track One sets a goal of final disposition within twelve months, on average, from the date Track One status is granted, while the current PPH target addresses the timing of the first action rather than promising final disposition. Prioritized Examination FAQs, supra, at 9, Q.22; U.S. Patent & Trademark Off., USPTO’s Prioritized Patent Examination Program (last visited July 27, 2026); U.S. Patent & Trademark Off., Patent Prosecution Highway, supra.

The practical decision is therefore not simply whether the applicant wants speed. It is whether the applicant wants speed on the claim set that another authority has already evaluated. If yes, PPH is often the cleaner and less expensive route. If the U.S. claim strategy materially departs from the favorable work product, Track One in a § 111(a) filing—or ordinary examination—may preserve more valuable flexibility.

IX.             Conclusion

An all-“A” PCT search can be the beginning of an effective U.S. acceleration strategy, but it is not the legal endpoint. The applicant must confirm that the WO/ISA, WO/IPEA, or IPRP positively assesses at least one claim for novelty, inventive step, and industrial applicability; determine that the assessment reflects a meaningful search; and align every U.S. claim with the positively assessed subject matter.

Section 371 presents no categorical barrier. A PPH request may be filed with the national-stage papers, and the current USPTO form can also function as an express request for early commencement of national-stage processing. But the form, national-stage requirements, PCT work product, claim-correspondence table, preliminary amendment, and IDS must work together.

The best time to plan for PPH is therefore not the day the U.S. national stage is filed. It is when the PCT claims are drafted and prosecuted. Planning for later PPH use does not mean indiscriminately adding every desired U.S. claim category to the PCT application. Those categories must be drafted so that they receive a complete international search and affirmative Box V findings. A system or medium claim that appears in the PCT application but is excluded from the opinion, left unsearched after a unity determination because additional search fees were not paid, or otherwise denied an opinion does not provide the needed PPH predicate. PCT ISPE Guidelines, supra, ¶¶ 17.32–.42.

A PCT claim set that both anticipates the desired U.S. statutory categories and secures a meaningful positive assessment can preserve acceleration and portfolio flexibility. A claim set designed without that later use in mind may leave the applicant with a harder choice: take the highway on claims already approved elsewhere, or leave it to pursue the claims that matter most in the United States.