m) Prima facie relevance 

A finding of prima facie relevance has not been considered a sufficient reason on its own for admission at this stage of the proceedings (see, for example, T 2113/17, T 187/18, T 482/18, T 1042/18, T 741/20 and T 1305/21). However, depending on the circumstances of the case, prima facie relevance has been regarded as a possible factor when considering Art. 13(2) RPBA (see, for example, T 574/17, T 2391/18, T 463/19 and T 307/22).

In T 187/18 the board first noted that the appellant's (opponent's) new line of attack against claim 1 based on a new combination of documents was a change to its case. It then recalled that, according to Art. 13(2) RPBA, exceptional circumstances justified by cogent reasons were required and that therefore alleged prima facie relevance was not per se a consideration. Since the appellant did not identify any special reasons for the amendment to its case, the board did not admit this new line of attack into the proceedings. See also T 1042/18 (in which the board found that the possibility that a piece of evidence might be prima facie relevant was not sufficient on its own) and T 1876/18 (underlining that such an interpretation of the requirements of Art. 13(2) RPBA would allow the indiscriminate admittance of any relevant evidence and objections even if filed at the latest stage of the proceedings which would clearly be against the principle of procedural economy); similarly T 1305/21.

In T 482/18 it was not until the oral proceedings on appeal that the appellant (opponent) raised objections under Art. 123(2) and 84 EPC to a term in the claims according to the main request (identical to the auxiliary request on the basis of which the opposition division had maintained the patent). The board rejected the opponent's argument that under Art. 114(1) EPC 1973 it had to examine compliance with the requirements of Art. 123(2) and 84 EPC of its own motion. It also did not agree that the new submissions were no more than arguments based on facts already at issue in the proceedings. Moreover, it explained that the criterion of prima facie relevance, which the boards – generally rightly – still considered even though it was not referred to in Art. 13(1) RPBA, could not be decisive here in view of the stage reached in the proceedings and the fact that the new submissions had not been occasioned by any statements made in the proceedings before the board.

The board in T 574/17 confirmed that when exercising its discretion under Art. 13(2) RPBA, a board may also rely on the criteria referred to in Art. 13(1) RPBA. This discretion was inherent to the assessment of whether there were "exceptional circumstances" and was furthermore expressed by the phrase "in principle" (T 172/17). The board noted that the criteria referred to in Art. 13(1) RPBA included the suitability of the amendment to resolve the issues raised. In the case in hand, this translated into whether the newly raised objections against auxiliary request 14 would prima facie be successful. The board pointed out however that it was not necessary to assess the prima facie relevance of an objection in order to conclude that there were no exceptional circumstances under Art. 13(2) RPBA (see T 2787/17). Whether it was appropriate to conduct this kind of prima facie assessment depended on the specific circumstances of the case. The case at issue was characterised by the fact that the opposition division had maintained the patent as granted. Auxiliary request 14 had never been examined or objected to. In this specific procedural situation, the board found it appropriate to consider the (lack of) prima facie relevance of the two objections raised for the first time in the oral proceedings before the board. The board explained in this context that the obiter dictum in G 10/91, point 19 of the Reasons, was fully respected when the prima facie relevance of an objection was considered in the context of assessing whether there were exceptional circumstances justifying its admittance pursuant to Art. 13(2) RPBA.

In T 463/19, the board decided to take the opponent's late-filed document E65a into account under Art. 13(1) and (2) RPBA, in view of the following exceptional circumstances. The document had been objectively difficult to find. It had undoubtedly not been withheld intentionally, with the opponent only becoming aware of it after it had been cited for the first time by a third party in other opposition proceedings. In the board's view, it was prima facie part of the state of the art and was prima facie very relevant.