In R 2/15 of 21 November 2016 date: 2016-11-21 the Enlarged Board held that petitions for review of interlocutory decisions were not generally inadmissible (see also R 5/08, R 5/15). The Enlarged Board saw no reason to assume that Art. 106(2) EPC, which stipulates that a decision which does not terminate proceedings as regards one of the parties can, as a rule, only be appealed together with the final decision, was to be applied to the petition for review procedure. Neither Art. 112a EPC nor R. 104 to 110 EPC contained a provision corresponding to Art. 106(2) EPC.

In R 5/15 the Enlarged Board acknowledged that interlocutory decisions dealing with objections of suspected partiality unquestionably had consequences of utmost importance for the proceedings as a whole. The petitioner had argued that it was likely that the Enlarged Board would set aside the decision of the board in its alternate and that the board had violated its right to be heard by failing to consider its request for postponement. The Enlarged Board held it was not appropriate to base a decision on speculation. The interlocutory decision of the Board in its alternate composition was binding and had the force of res judicata.