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Supplementary International Search under PCT

In addition to International Search conducted by an International Searching Authority (ISA), under Patent Cooperation Treaty (PCT) an Applicant can have his/her international patent application searched more comprehensively under Supplementary International Search (SIS). This additional search reduces risk of discovering new relevant documents and technical literature in national phase of the international application. SIS aims to identify published documents that may not have been found by an ISA that carried out the international search because of diversity of prior art in different languages and different technical fields.[1]

PCT identified the problem of massive increase in technical documents and disclosures in range of languages that makes difficult for a single ISA to identify relevant prior arts. Additionally, in various instances, translations are not available or not as reliable as the original source, which elevates the problems for Examiners in carrying out a search. To address this problem PCT came up with SIS, which allows an Applicant to have a search conducted by any searching authority of his choice that are authorized to carry out SIS. Generally, Supplementary International Searching Authority (SISA) is irrespective of receiving office where the application was filed.

For instance, if an Applicant has received an ISR from an ISA Abc, but the Applicant feels that there could be some references of another language which ISA Abc could not locate, the Applicant can apply for an SIS to an SISA that is competent to search in that language.

If the Applicant requires an SIS to be carried out, he/she can submit a request to International Bureau (IB) within 22 months from the priority date and pay relevant fees within one month of submitting the request. It is expected that a request for SIS will usually only be made after the applicant has seen and considered the International Search Report (ISR); however this is not a requirement.[2] Also, IB will not transmit any copy of the international application and supplementary search request to the SISA before date of receipt of the ISR by IB or expiration of 17 months from the priority date, whichever occurs first.[3] According to PCT Information Service, the request for SIS can be made at the time of filing; however, it would be unusual to do so before the results of the main search (ISR) are available. Thus, to provide clarity, an Applicant can request for an SIS any time within 22 months from date of priority of an international application, even at the time of filing, if the Applicant requires comprehensive search from more than one search authorities; however, the request may not be processed before date of receipt of the ISR by the IB or before expiration of 17 months from date of priority, whichever falls earlier.

The Supplementary International Search Report (SISR) generally contains a listing of references to patent documents and other technical literature which may affect patentability of the invention disclosed in the international application other than the documents which have already been cited in the ISR. SISR can include already cited documents in case they are necessary because of new relevance when read in conjunction with other documents discovered during the SIS. Occasionally, SISR can contain more detailed explanations than those in the ISR.[4]

To conclude, an Applicant can strategically plan the course of action which he/she wishes to take pertaining to international search. SIS can be helpful when an Applicant requires additional search in a different language than that of the ISR. From investment point of view, SIS can save a large sum of the Applicant while proceeding in national phases with more comprehensive view of the prior arts.

[1] PCT FAQs,

[3] Rule 45bis. 4(e), Regulations under the PCT(as in force from July 1, 2017),

[4] Supra Note 1

About the Author: Ms. Prigya Arora, Patent Associate at Khurana & Khurana, Advocates and IP Attorneys. Can be reached at [email protected]

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