5.1.3 Amendments occasioned by national prior rights

In T 15/01 (OJ 2006, 153) the board made it clear that the general purpose of R. 57a EPC 1973 (R. 80 EPC) was to allow amendments only where they were made to overcome an objection against the validity of the European patent. It followed from the reference to R. 87 EPC 1973 (R. 138 EPC) that, within the framework of the centralised opposition procedure before the EPO, amendments were also to be allowed where the patentee intended to overcome a possible ground of invalidity which only existed in respect of a particular contracting state. Thus, R. 57a EPC 1973 was not infringed by the formulation of a separate set of claims for a contracting state in which, due to a reservation made under Art. 167(2)(a) EPC 1973, certain product claims as granted would be considered invalid or ineffective.