The duty of a proprietor to timely file Auxiliary Requests is discussed in T 0217/23.

European Patent No. 3 389 691, concerning NTCP-targeting peptides, was revoked after the Board refused to admit auxiliary requests filed for the first time with the grounds of appeal. The Board stressed that proprietors must address objections raised in the notice of opposition by presenting fallback positions at the earliest stage, rather than waiting for a favourable preliminary opinion. Late filing undermines procedural economy and fairness to opponents, and absent exceptional circumstances, such requests will not be admitted under the RPBA.

Background

European Patent No. 3 389 691, titled “Cyclic NTCP-targeting peptides and their uses as entry inhibitors” was opposed on grounds of added subject-matter, insufficiency of disclosure, and lack of inventive step. The opposition division (OD) maintained the patent in amended form.

The Appeal

The opponent (O) - appellant (A) appealed the OD’s decision, inter alia contesting the ODs reasoning on added subject matter. With the reply to the statement of grounds of appeal, the proprietor - respondent (R) filed sets of claims of a main request (MR) and two auxiliary requests (AR). The MR was identical to the request held allowable by the OD. AR1 and 2 1 and 2 were newly filed in appeal.

The Board summoned the parties for oral proceedings and in a communication pursuant to Art 15(1) RPBA, informed the parties of its preliminary opinion that, inter alia, the MR did not meet the requirements of Art 123(2) EPC and that AR 1 and 2 were not to be admitted into the appeal proceedings.

The A withdrew their request for oral proceedings and informed that it would not attend oral proceedings.

R filed further arguments and further sets of claims of corrected AR 1 and AR 1a and 2a. It informed the board that it would not attend the oral proceedings. The board consequently cancelled the oral proceedings and decided the case on the basis of the written submissions of the parties. 

The Board came to the view that the subject matter of the MR extended beyond the content of the application as filed. 

The Board then assessed whether an AR filed for the first time in appeal proceedings could be admitted. AR 1 and 2 were considered amendments to the respondent’s case under Art 12(4) RPBA because they were not admissibly raised and maintained during opposition proceedings. According to Art 12(6) RPBA, such amendments should not be admitted unless circumstances of the appeal justify their late filing. 

The Board noted that the objections addressed by these requests had been raised in the notice of opposition. The proprietor chose not to file fallback positions during opposition and relied solely on argument. Filing these AR’s only on appeal was therefore considered unjustified.

R argued that filing numerous AR during opposition would have been against procedural economy and that the positive preliminary opinion of the OD provided no reason to file additional ARs. 

The Board rejected this reasoning, emphasizing that 

The Board stressed that parties must submit all facts, evidence, arguments, and amendments as early and completely as possible to ensure fairness and procedural efficiency. The duty to file AR cannot depend solely on the OD’s opinion, as this would shift responsibility from P to the OD and disadvantage the O. The main lines of defence should emerge in the proprietor’s initial observations under Rule 79(1) EPC. For these reasons, the Board refused to admit AR 1 and 2 under Art 12(6) RPBA.

Similarly, AR1a, 2a, and corrected AR1, filed after the Board’s communication under Article 15(1) RPBA, were considered late amendments governed by Art 13(2) RPBA 2020. Such amendments are, in principle, not taken into account unless exceptional circumstances exist, justified by cogent reasons. R cited procedural economy but did not withdraw higher-ranking requests or explain why these amendments were not filed earlier in response to the appeal grounds. Moreover, these requests contained similar limitations as AR 1 and 2, which had already been refused. Consequently, the Board found no exceptional circumstances and decided not to admit these requests under Art13(2) RPBA.

The Boards decision

In conclusion, the Board held that the late filing of AR without justified reasons violated the principles of fairness and procedural economy. Therefore, none of the AR were admitted, and the patent was revoked.

Summary written by the NLO EPO Case Law Team