f) Late substantiation of lines of attack – additional complexity – procedural economy – submissions not admitted 

In T 2227/15, applying Art. 13(1) RPBA 2020 as well as Art. 13(1) and (3) RPBA 2007, the board did not admit the appellant's inventive-step attack based on D1 in combination with common general knowledge. The board considered that this attack had been substantiated for the first time at the oral proceedings before it; the appellant's earlier general submissions on inventive step were regarded as unsubstantiated and were not taken into consideration, since they did not constitute the party's complete case within the meaning of Art. 12(2) RPBA 2007, which corresponded to Art. 12(3) RPBA 2020. In reply to the board's communication, the appellant had provided neither substantiated arguments nor comments on the preliminary opinion of the board in this regard. Thus, in the board's view, the respondent had every reason to believe that a lack of inventive step objection was no longer being pursued. Considering all the circumstances of the case, the board concluded that admitting this attack into the proceedings would not only substantially add to and considerably change the complexity of the matter to be discussed, but would also be contrary to the need for procedural economy and would take the respondent by surprise.

In T 1217/17 the board, referring to Art. 12(2) and (4) RPBA 2007, decided to disregard several lines of attack set out in the reply to the appeal on the basis that they were not sufficiently substantiated. At the oral proceedings, the respondent (opponent) announced an "expansion" on its submissions, but the board considered that this would substantially amend its appeal case (see abstract in chapter V.A.4.2.2k)). Exercising the discretion conferred on it under Art. 13(1) RPBA 2020 (Art. 13(2) RPBA 2020 was not yet applicable), the board took account, in particular, of the stage reached in the proceedings and the need for procedural economy. It observed that the submissions in question were entirely new and, if admitted, would have introduced complex new issues at a very late stage in the proceedings, and the ensuing discussion would inevitably be detrimental to procedural economy. In such circumstances, the appellant could not be required to come up at short notice with a defence against attacks first launched at the oral proceedings.