According to T 1500/10, the notice in OJ 2008, 471 together with R. 115(2) EPC make it clear that the oral proceedings are themselves an opportunity for the applicant to present its comments, in accordance with Art. 113(1) EPC. If a party decides not to attend the oral proceedings without a serious reason, it chooses not to make use of the opportunity to comment at the oral proceedings on any of the objections raised during them, and it has no right to make additional written submissions. Serious reasons are the same reasons that could justify postponement of oral proceedings (see in this chapter III.C.6.1.4).
On the question of whether a decision pronounced against a party who has chosen not to attend oral proceedings may be based on new facts, evidence and/or arguments introduced during those oral proceedings, see chapter III.B.2.7. "The right to be heard in case of the non-attendance at oral proceedings". As to the case law where the appellant (applicant) submits new claims after oral proceedings have been arranged by the board of appeal and then does not attend those proceedings, see the chapter V.A.4.5.3 a) "Absence of applicant (patent proprietor) from oral proceedings".
Source: http://www.epo.org/law-practice/legal-texts/html/caselaw/2019/e/clr_iii_c_5_1.htm
Date retrieved: 17 May 2021