PCT Search

PCT International Patent Application Search

The PCT international patent application search framework plays a central role in evaluating the patentability of an invention before national phase entry. Conducted under the Patent Cooperation Treaty (PCT), this mechanism provides applicants with early, structured insight into prior art, novelty, inventive step, and industrial applicability, supporting informed global patent strategy decisions.

A. International Search Report (ISR) by the International Searching Authority (ISA)

A competent International Searching Authority (ISA) conducts an international prior art search to identify relevant published documents relating to the claimed invention. Based on this search, the ISA issues an International Search Report (ISR) along with an accompanying Written Opinion (WO).

The ISR primarily cites documents considered most relevant to assessing the novelty and inventive step of the invention. It serves as an important reference point for applicants when evaluating the strength of their international patent application.

B. Written Opinion (WO) of the International Searching Authority

The Written Opinion (WO) of the ISA is a non-binding assessment issued together with the ISR. It provides a preliminary evaluation of whether the claimed invention appears to:

• Be novel
• Involve an inventive step (non-obviousness)
• Be industrially applicable

The WO is prepared in the same language as the ISR and is communicated to both the applicant and the International Bureau (IB) of WIPO.

As a general rule, the ISA establishes the ISR and WO within:

• Three months from receipt of the search copy from the Receiving Office, or
• Nine months from the priority date,
  whichever period expires later.

Informal Comments on the Written Opinion

Applicants may submit informal comments in response to the WO to the International Bureau. These comments allow applicants to present counterarguments or clarifications, particularly in situations where international preliminary examination is not requested. Such comments may later be forwarded to designated national offices.

C. International Preliminary Report on Patentability (IPRP) – Chapter I

Where no international preliminary examination under Chapter II is requested, the Written Opinion of the ISA forms the basis for the issuance of the International Preliminary Report on Patentability (IPRP) under Chapter I of the PCT.

The IPRP is prepared by the International Bureau on behalf of the ISA and is communicated to all Designated Offices, together with any informal comments submitted by the applicant. The IPRP under Chapter I becomes publicly available after 30 months from the priority date.

D. Supplementary International Search

In addition to the main international search, applicants may request one or more Supplementary International Searches (SIS). These searches are conducted by designated international authorities and are intended to expand the linguistic and technical scope of the prior art search.

A supplementary international search can help reduce the risk of previously unidentified prior art emerging during national phase prosecution.

Key procedural aspects include:

• The request must be filed after receipt of the main ISR
• The deadline for requesting a supplementary international search is 19 months from the priority date
• Separate requests must be submitted for each supplementary search
• Requests must be filed in English or French
• The Supplementary International Search Report is generally established within 28 months from the priority date

E. International Preliminary Examination (IPE) – Chapter II

Applicants seeking a more detailed, non-binding evaluation of patentability may file a demand for International Preliminary Examination (IPE) under Chapter II of the PCT using the prescribed form.

The IPE is conducted by a competent International Preliminary Examining Authority (IPEA) and provides an opinion on:

• Novelty
• Inventive step
• Industrial applicability

The demand must be submitted directly to an IPEA that is competent for the specific international application, as designated by the relevant Receiving Office.

Effects of International Preliminary Examination

The outcome of the IPE is the International Preliminary Report on Patentability (IPRP) under Chapter II. This report assists applicants in assessing the likelihood of obtaining patent grants in elected national offices.

Additionally, filing a valid demand for IPE typically results in the deferral of national phase entry in elected states until 30 months from the priority date (or longer in certain jurisdictions), provided the demand is filed before 19 months from the priority date.

Time Limits for Filing a Demand for IPE

A demand for international preliminary examination may be filed before the later of:

1. Three months from the date of transmittal of the ISR and WO (or declaration that no ISR will be established), or
2. 22 months from the priority date

Importance of PCT Search and Examination for Global Patent Strategy

For startups, MSMEs, and foreign applicants, the PCT international patent search and examination process provides early, structured insight into patentability risks and opportunities. These reports often influence claim drafting, jurisdiction selection, and investment or commercialization decisions prior to entering national phases.