3.3 Refusal to perform a (full) international search
3.3.5.Complex applications
3.3.008Furthermore, the EPO as ISA will in exceptional cases not perform an international search or will perform a search limited to parts of the claimed subject-matter if the application documents fail to comply with the prescribed requirements to such an extent that a meaningful search is impossible for all or part of the claims. Applications of this kind are often referred to as "complex applications".
3.3.009Complex applications will be dealt with in accordance with the PCT‑EPO Guidelines and the ISPE Guidelines supplemented, where appropriate, by the EPO's practice as set out in the Guidelines for Examination (GL/EPO) (see points 1.4.001-1.4.006).
3.3.010Before taking a decision under Article 17(2)(a)(ii) PCT, the ISA may invite the applicant informally to provide clarification of the claimed subject-matter in accordance with paragraphs GL/ISPE 9.34 and GL/ISPE 9.35 of the ISPE Guidelines.