5.15.007If the application documents which are to serve as the basis for the supplementary European search do not comply with the requirement of unity of invention, applicants are invited under Rule 164(1)(b) EPC to pay a further search fee for each invention other than the first invention mentioned in the claims. If they wish to pay further search fees in response to the invitation under Rule 164(1)(b) EPC, they must do so within the time limit of two months set in the invitation. This period is excluded from further processing under Rule 135(2) EPC.
5.15.008Together with the invitation, a partial supplementary European search report together with a provisional opinion on the patentability of the invention (or unitary group of inventions) is drawn up on the invention or group of inventions first mentioned in the claims.
5.15.009The supplementary European search report is then drawn up for the parts of the application relating to inventions for which search fees have been paid. In reply to the accompanying search opinion, the applicant must select, from all inventions searched by the EPO, a single invention to be prosecuted in the European grant procedure. For the other inventions the applicant may file divisional applications.
5.15.010Although the EPO is in no way bound by the opinion of the ISA on the issue of whether the application meets the requirement of unity, the EPO will in many cases share that opinion, given that the practices of the ISAs are based on the same guidelines (Chapter 10 of the ISPE Guidelines). Therefore, where the (S)ISA considered the requirement of unity not to be met, the applicant is advised to amend the application in due time (i.e. before expiry of the period under Rule 161(2) EPC) in such a way that the invention on which the applicant wishes the supplementary European search and the examination to be based is that first mentioned in the claims, since if the EPO agrees with the ISA on lack of unity, this invention will then be searched on the basis of the search fee paid according to Rule 159(1)(e) EPC, without the need to pay any additional search fees according to Rule 164(1) EPC, which do not qualify for a fee reduction according to Article 153(7) EPC.