Where the EPO can base the ISR on an earlier search that it has performed oncarried out for an application whose priority is validly claimed for the international application, the international search fee paid will be refunded in part or in full, depending uponon the extent to which the EPO benefits from that earlier search (see point 148).
WIPO PCT Guide 5.073
No refund is made for an earlier search that was not carried out by the EPO itself and/or if priority has not been validly claimed (see point 149).
Source: http://www.epo.org/applying/international/guide-for-applicants/html/e/ga_c_i_11.html
Date retrieved: 24 November 2017