Abstract on Article 12(6) RPBA for the decision T1319/23 of 05.09.2025

In T 1319/23 the appeal lay from the decision of the opposition division revoking the European patent concerned. According to the appealed decision neither the main request nor auxiliary request 1 met the requirement of sufficiency of disclosure. One of the main points of dispute between the parties during the opposition proceedings related to the impossibility to perform TREF measurements with a particular solvent in a certain temperature range. In its statement of grounds of appeal, the appellant (proprietor) submitted two lines of argument regarding sufficiency of disclosure. In section C.1, it argued that the arguments retained by the opposition division to reach their decision on this point were related to a potential clarity issue rather than sufficiency of disclosure. In section C.4, it submitted that even if the issue identified in the appealed decision related to sufficiency of disclosure, these concerns were irrelevant for most polymers and at most would affect the extreme boundaries of the claim. The board observed that undisputedly the appellant had not put forward these arguments during the opposition proceedings and concluded that they constituted an amendment to the appellant’s case (Art. 12(2) and (4) RPBA). Their admittance was therefore at the board’s discretion pursuant to Art. 12(4) and (6) RPBA. Considering that the main request is the patent as granted, the board agreed with the respondent that these arguments could have been submitted earlier. However, in the board’s view, the appellant was not using the arguments in section C.4 to build a fresh case in appeal. Rather they were strictly linked to a central point of the decision under appeal and merely represented a further development of an existing line of argument, which remained within the same framework of the line of defence adopted in opposition proceedings. In certain aspects, they were also a response to specific concerns expressed by the opposition division in the impugned decision. Moreover, the board considered that whether an objection relates to clarity or sufficiency of disclosure was a purely legal issue. Contrary to the respondent's view, it could not be disregarded since it was the board's duty to ensure that the parties address the correct legal basis during the proceedings and that this legal basis is the one eventually considered when reaching a decision on the disputed issue. In this regard, the board agreed with the appellant that these arguments concerned the correct application of the law to the underlying facts and were not directed to the presentation of new facts. The board also noted that Art. 12(4) RPBA, which states that the board should, when exercising its discretion, take into account the complexity of the amendment, could not be interpreted as meaning that such additional arguments should be disregarded automatically because of this inherent increased complexity. In view of the above, the board decided to exercise its discretion pursuant to Art. 12(4) RPBA to admit into the proceedings the arguments put forward by the appellant in sections C.1 and C.4 of the statement of grounds of appeal. Based on these arguments, the board concluded that the issue related to the impossibility to perform TREF measurements in a certain (marginal) temperature range, did not amount to a lack of sufficiency of disclosure pursuant to Art. 100(b) EPC and remitted the case for further prosecution.