International Preliminary Report on Patentability (IPRP Chapter I)

An International Preliminary Report on Patentability (IPRP) Chapter I is a report issued under the Patent Cooperation Treaty (PCT) that gives a preliminary, non-binding opinion on whether a PCT application appears to satisfy novelty, inventive step, and industrial applicability. It is established by the International Bureau of WIPO based on the Written Opinion of the International Searching Authority (ISA), and it is issued whenever the applicant does not file a demand for international preliminary examination under Chapter II.

What the IPRP Chapter I Actually Is

Every PCT application goes through an International Search, which produces two documents: the International Search Report (ISR), listing relevant prior art, and the Written Opinion of the ISA, a preliminary assessment of patentability based on that prior art.

If the applicant takes no further action — specifically, does not file a Chapter II demand for international preliminary examination — the International Bureau converts that Written Opinion into the IPRP Chapter I and communicates it to every designated national and regional office. No new substantive examination happens at this stage. Chapter I is essentially the ISA's written opinion, repackaged and distributed under the International Bureau's letterhead.

When It Is Issued

The IPRP Chapter I is established promptly after the expiration of the time limit for filing a Chapter II demand (generally 22 months from the priority date, or 3 months from transmittal of the ISR, whichever is later), and it is communicated to designated offices shortly before the 30-month national-phase entry deadline most countries apply.

Is It Binding on National Patent Offices?

No. The IPRP Chapter I is advisory only. Each national or regional patent office applies its own patentability standards during the national phase and is free to reach a different conclusion — favorable or unfavorable — than the one stated in the report. A negative IPRP does not prevent national-phase filing, and a positive one does not guarantee grant.

ISR, Written Opinion, IPRP Chapter I, and IPRP Chapter II Compared

Chapter I vs. Chapter II: The Key Difference

Chapter I requires no extra filing or fee — it happens automatically if the applicant does nothing after the Written Opinion. Chapter II requires the applicant to affirmatively file a demand and pay a fee, but in exchange the applicant can amend the claims and submit arguments before the IPEA issues its report. In practice, applicants file a Chapter II demand specifically when the Written Opinion was unfavorable and they want a chance to argue or amend before the report is locked in and sent to every designated office.

What Happens After a Negative IPRP?

A negative IPRP Chapter I does not end the application. The applicant can still enter the national phase in any designated country and prosecute normally — including filing amendments, arguments, and responding to office actions under that country's own law. Some applicants treat a negative Chapter I as a signal to narrow claims before national-phase entry, or to abandon protection in countries where the cost of prosecution is unlikely to be worth it given the report's findings.

Patent Bar Relevance

The USPTO Patent Bar Exam tests PCT procedure under MPEP Chapter 1800. Candidates should be able to identify: (1) that Chapter I issues automatically absent a Chapter II demand, (2) that the IPRP is never binding on national offices, and (3) the practical effect of a demand — the opportunity to amend and argue before the report issues. Confusing Chapter I with Chapter II, or assuming the IPRP determines patentability outright, are common wrong-answer traps on exam questions covering this topic.