PA 08/2008: The consequences of a finding by the ISA of lack of unity of invention

Q: I have received Form PCT/ISA/206 (“Invitation to pay additional fees and, where applicable, protest fee”) from the International Searching Authority (ISA) in respect of an international application, stating that there are three inventions claimed in the application. I have therefore been invited to pay two additional search fees to cover each additional invention. I do not agree with the finding by the ISA of lack of unity of invention. What will happen if I fail to pay the additional search fees? If I pay only one additional fee, can I choose which additional invention I wish to be searched? Is it possible to protest against the ISA’s finding of lack of unity?

A: According to PCT Rule 13.1, the international application must relate to one invention only or to a group of inventions so linked as to form a single general inventive concept (“requirement of unity of invention”). The search fee is intended to cover the cost for the ISA to carry out an international search on the international application, but only to the extent that the international application meets the requirement of “unity of invention”. Therefore, if that requirement is not met, the ISA is entitled to request the applicant to pay an additional search fee for each invention beyond the first which is to be searched (see PCT Rule 40.1). Further details on the requirement of unity of invention can be found in the Administrative Instructions under the PCT, Annex B, at:

as well as in the PCT Applicant’s Guide, International Phase, paragraphs 129–138 at:

Consequence of the failure to pay the additional search fees

As in your case, ISAs will invite the applicant to pay additional search fees by way of Form PCT/ISA/206. Some ISAs will attach to that invitation the results of a “partial” international search (this is not to be confused with the international search report (ISR)), limited to the invention first mentioned in the claims (the “main invention”) (see PCT Article 17(3)(a) ).

If you fail to pay the additional search fees within one month from the date of mailing of the invitation (note that this time limit cannot be extended), no searches of additional inventions will be made and the ISR, when it is established, will only cover the first claimed invention (where a partial search was furnished to the applicant, the results of that partial search only will be included in the ISR). If you do not pay all requested additional search fees, the ISA will only search the number of inventions covered by the payment — upon payment, it should be possible for you to specify to the ISA which claims you wish to be searched. If you pay all the additional fees within the applicable time limit, the ISR will include the results of the search of all inventions in the application.

If you disagree with the ISA’s finding under PCT Rule 40 of lack of unity of invention (or, in the number of additional search fees that you have been invited to pay), you may, under PCT Rule 40.2(c), protest against that finding, as explained below.

Protest procedure and, where applicable, protest fee

In order to initiate the protest procedure, you must pay the additional search fees within the time limit fixed by the ISA in Form PCT/ISA/206 (one month) for all inventions in respect of which you are still interested in receiving an ISR, and send a reasoned statement explaining why you consider that unity of invention has been complied with, or that the number of additional fees required is excessive. After payment of the fees, your protest will then be examined by a review body constituted in the framework of the ISA, which, if it finds your protest justified, would order the total or partial reimbursement to you of the additional fees.

In accordance with PCT Rule 40.2(e), such a protest may also be subjected by the ISA to the payment of a “protest fee” (currently, only five International Searching and Preliminary Examining Authorities charge such a fee. For details, consult the PCT Applicant’s Guide, Annex D, for the ISA concerned). Note however that, although an additional search fee is required for each separate invention, only one protest fee is payable, where applicable, regardless of the number of additional search fees that you have been invited to pay. The protest fee is refunded if the review finds that the protest was fully justified. If you fail to pay the protest fee within the applicable time limit, the ISA will declare that the protest has been considered not to have been made. 

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