Art. 12(2) RPBA provides that the statement of grounds of appeal should specify expressly all the facts, arguments and evidence relied on by the party. Under Art. 13(1) RPBA the boards have discretion to admit and consider any amendment to a party's case after it has filed its grounds of appeal or reply. To the extent that the decision of the Enlarged Board of Appeal in G 4/92 (OJ 1994, 149) deals with the general admissibility of new arguments in appeal proceedings, it must be taken to have been modified by the amendments to the RPBA introduced with effect from 1 May 2003 (T 1621/09).
Filing with the statement setting out the grounds of appeal, new documents reinforcing the line of attack already made before the department of first instance had to be considered as the normal behaviour of a losing party and did not constitute an abuse of procedure (T 113/96, T 1034/01, T 1177/04, T 1267/05).
In the ex parte case T 704/06, the applicant/appellant raised a new inventive step argument during the oral proceedings which the board admitted into the proceedings. This argument amounted to an entirely new approach with regard to inventive step. The appellant's argument was simultaneously new and late-filed. The board stated that in accordance with the case law, Art. 114(2) EPC does not provide a legal basis for disregarding late-filed arguments on the grounds that they were presented for the first time at the oral proceedings (T 92/92). It is the very purpose of appeal proceedings, particularly oral proceedings, to provide an opportunity for a losing party to throw new light on relevant aspects of matters which have been decided to its detriment (T 86/94). The appellant is not bound to the line of arguments it used in the statement of grounds for the entire appeal proceedings (T 432/94).
In T 671/08 the late filed argument was exceptionally admitted despite causing adjournment of the oral proceedings. The board considered the appellant/opponent's objection of insufficient disclosure to be a fundamental one that could not be ignored. The board stated that the fundamental nature of the new objection would render any discussions on novelty and inventive step meaningless, had it been left unresolved. This case was an exception to the principles set out in Art. 13(3) RPBA where amendments to a party's case should not be admitted into the proceedings when their admission would lead to an adjournment of the oral proceedings. Art. 23 RPBA specified namely that the Rules of Procedure shall be binding on the boards of appeal, provided that they do not lead to a situation which would be incompatible with the spirit and purpose of the Convention. Not admitting this objection would have gone against the principle of examination of its own motion enshrined in Art. 114(1) EPC 1973, since Art. 114(2) EPC 1973, which limits this principle and gives the EPO the discretion to disregard late filed facts or evidence, does not apply to late filed arguments.
In some decisions it has been observed that new arguments first put forward at the oral proceedings without any reasonable explanation or justification are to be regarded as late filed and not admitted into the proceedings (T 1069/08, T 775/09, T 1621/09).
In T 1621/09 the board held that a new argument brought forward in appeal proceedings by a party which would have the effect of amending its case, even if the argument is based on evidence and facts already in the proceedings, can only be introduced into the proceedings at the discretion of the board of appeal by way of an amendment under Art. 13 RPBA. The board dealt with the following question: where a new argument is put forward for the first time at oral proceedings, how is the exercise of the board's discretion to admit the amendment affected if the party prejudiced is not present at the oral proceedings? The board stated that Art. 13(2) RPBA must be read subject to Art. 15(3) RPBA, with the result that the absence of a duly summoned party does not prevent a board from allowing an amendment to another party's case and reaching a decision on the basis of the amended case. The absence of the party is nevertheless a factor to be taken into account in the exercise of the discretion. In the case at issue the board decided however not to allow the appellant to amend its case.
In T 1069/08 it was only at the oral proceedings that the appellant/opponent asked the board for an opportunity to present its arguments on the lack of obviousness of the claimed subject-matter. This request was refused by the board for the following reasons: The appellant's statement of grounds of appeal did not include any argument regarding the obviousness of the claimed subject-matter. Hence, the introduction of this new argument at oral proceedings represented an amendment to the appellant's case (Art. 13(1) RPBA). The appellant's failure to submit the new argument in reply to the board's communication deprived the respondents of the opportunity to present their comments thereon and/or of the opportunity to reconsider their intention not to attend the oral proceedings.
In T 775/09, the party as of right's second line of argument was based on a number of citations first referred to at the oral proceedings on appeal. The board observed that such an amendment to the party's case at this stage gave rise to combinations and facts of a complex nature which had not previously been addressed during the written proceedings. In accordance with the case law discussed above, the board exercised its discretion under Art. 13(1) RPBA and refused to admit the new argument at such a late stage of the appeal proceedings.
In T 161/09 the board decided to use its discretionary power to admit the appellants' first line of argument to the proceedings, in support of their objection of lack of inventive step, despite these submissions having been made only during the oral proceedings and having been contested as being inadmissible by the respondent. In the view of the board these submissions did not alter the legal and factual framework of the proceedings, given that the appellants' first line of argument was essentially based on D1, neither did the second line of argument, which was already presented in the grounds of appeal and did not include any fresh filed evidence. Thus, by submitting the first line of argument at the oral proceedings the appellants did not amend their case, as set out in the grounds of appeal, in a substantial manner.