In view of the above considerations, all amendments made to claims and any connected amendments to the description and drawings in the course of opposition proceedings, such as a change in the technical features of the invention, must be examined to determine whether such amendments could result in the extension of the subject-matter beyond the content of the application as originally filed (Art. 123(2)) or in the extension of the protection conferred (Art. 123(3)).

If, in view of Art. 84 and Art. 69, the application documents have been adapted to amended claims before grant, thereby deleting part of the subject-matter originally disclosed in order to avoid inconsistencies in the patent specification, as a rule, subject-matter deleted for this reason cannot be reinserted either into the patent specification or into the claims as granted without infringing Art. 123(3) (the cut-off effect). An analogous finding applies to subject-matter retained in the patent specification during such adaptation for reasons of comprehensibility, but indicated as not relating to the claimed invention (see T 1149/97, OJ 6/2000, 259).

A possible conflict between the requirements of Art. 123(2) and 123(3) may occur where, in the procedure before grant, a feature was added to the application which is considered unallowable under Art. 123(2) in opposition proceedings. In that case, Art. 123(2) would require deletion of such a feature whereas Art. 123(3) would not allow deletion, as this would extend the protection conferred by the patent as granted. In such a case the patent will have to be revoked under Art. 100(c). However, where this feature can be replaced by a feature for which there is a basis in the application as filed and which does not extend the protection conferred by the patent as granted, maintenance in this amended form can be allowed. If the added feature, without providing a technical contribution to the subject-matter of the claimed invention, merely limits the protection conferred by the patent as granted by excluding protection for part of the subject-matter of the claimed invention as covered by the application as filed, this feature may be maintained (see G 1/93, OJ 8/1994, 541).

Other requirements of the EPC may also interact with Art. 123(3) after grant. For instance, if a patent as granted only contains claims that in fact define a "method for treatment of the human or animal body by therapy or surgery practised on the human or animal body" or contain such a method step, and such a patent is opposed under Art. 53(c), then Art. 53(c) and 123(3) may operate in combination so that the patent must inevitably be revoked, in that: