b) Party's duty to provide reasons for not submitting amendment at an earlier stage 

In T 2688/16 the board observed that it was a fundamental requirement under Art. 13(1) RPBA for consideration – at the board's discretion – of an amended appeal case that reasons be given for not making the amendment at an earlier stage in the proceedings. In the case in hand, a second experimental report filed with the patent proprietor's reply revealed a synergetic effect that was decisive for inventive step. The opponents contested the effect, but the board refused to admit the supporting evidence (in particular experimental reports), which they had not filed until about one month before the oral proceedings. The board observed that the opponents had had ample time (over 1.5 years) to file suitable evidence. A counter-example may be found in T 23/17 where the opponent's argument that new documents (filed about a year in advance of the oral proceedings) had been filed in response to experimental data produced by the patent proprietor in its reply was held plausible and understandable.

In T 256/17 the board refused to admit two new lines of attack based on lack of inventive step which the appellant (opponent) had filed in response to the respondent's reply to the statement of grounds of appeal. Both lines of attack were based on documents submitted during the first-instance proceedings. The appellant gave no reasons for first raising these objections after having filed the statement of grounds of appeal, and the board could see no reason for it either.

In T 1759/17 the appellant did not explain which allegedly new submissions of the respondent (patent proprietor) were to be addressed by the new documents and these were therefore not admitted.

In T 967/16 the board noted that the objection the respondents (proprietors) sought to overcome had already been raised in the notice of opposition. No reasons had been provided by the respondents why the auxiliary request in question could not have been filed at earlier stages of the proceedings.

For a further case where the party concerned did not provide any reasons for submitting new requests at this stage of the proceedings and the amendments were not admitted, see T 1005/22.

However, in T 938/14 the board exceptionally admitted auxiliary request 2, filed in response to the respondent’s submissions and identical to the main request underlying the decision under appeal, despite the fact that no justification was offered for the late reintroduction, as the request allowed the board to review the decision under appeal.

Whether the submissions should have been filed earlier is an important factor the boards have considered in exercising their discretion; see chapter V.A.4.4.5a) and V.A.4.4.6a) in particular.