Maiwald blog articles

All articles

EPO: No Backdoor Entry for New Third Party Observations in Appeal Proceedings; T 2255/15

In the recent appeal proceedings T 2255/15 before the European Patent Office´s Boards of Appeal, third party observations (TPO) were submitted only during the appeal stage. The (recently tightened) Rules of Proceedings of the Boards of Appeal (RPBA) on late-filing only impose constraints on late-file submissions by parties, as does Art. 114(2) EPC. A third party does not become party to the proceedings; so there arose the question: are these rules on late filing applicable to Third Party Observations?

The deciding Board of Appeal in T 2255/15 said: they can (and must).

Albeit observations by third parties pursuant to Article 115 EPC can in principle be filed during the appeal stage, Article 115 EPC must not be interpreted in such a way as to grant third parties rights which extend beyond those of the parties to proceedings (a finding that was already issued before, e.g., in G 2/19). Hence, the criteria laid down in Article 12(2) RPBA 2020 for parties to the proceedings are to be taken into consideration in deciding whether and to what extent Third Party Observations must be considered.

None of the objections raised in the TPO had been raised before in the opposition or appeal proceedings. According to the Board, the TPO did not constitute a direct and timely response to facts, objections, arguments or evidence on which the decision under appeal was based, and did not provide any argument why the impugned decision would not be correct.

The Board pointed out that the purpose of appeal proceedings is to review the opposition division’s decision rather than to start a second opposition proceedings. Admitting the new objections into the proceedings would have meant exactly that, namely it would have offered the third party and thus also the opponent a second go at opposition proceedings.

Therefore, the objections raised in the TPO were not admitted into the appeal proceedings.

Consequently, a TPO filed at appeal stage will be at high risk of being found inadmissible. Therefore, if a TPO is planned, its early filing during first instance opposition proceedings should be striven for.

Our blog contributions shall provide an overview with regard to legal topics, legislation and case law and are supposed to provide some general information rather than constituting any specific advice. Please do not hesitate to contact Maiwald and in particular the authors of the particular contributions if have any questions on the addressed topics or on other legal issues.

Contact us


Dr. Stefanie Parchmann


German Patent Attorney

European Patent Attorney