Where the EPO is a "designated Office" or an "elected Office" for an international application under the PCT, the application is equivalent to a regular European application (Euro-PCT application, Art. 153(2) EPC). In the case of Euro-PCT applications the provisions of the PCT apply in addition to those of the EPC, and where there is conflict between them, the provisions of the PCT prevail (Art. 150(2) EPC).
The case law concerning the EPO acting as designated or elected Office focuses on two areas. One concerns the competence of the EPO, in particular in the context of other authorities involved in the processing of international applications. The other deals with corrections of Euro-PCT applications, in particular correction of designation of states. Some decisions concern both areas. The case law concerned predominantly with the competence of the EPO is summarised below, while decisions concerned predominantly with corrections are summarised in IV.A.7.3, "Correction of designation of states (R. 139 EPC)". The issue of the language of proceedings in a Euro-PCT application is referred to under 3 below.