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 2020 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. It did not regard their merely stating that the evidence had been filed in response to its preliminary opinion or their pointing to shortcomings in the proprietor's experimental reports as amounting to adequate reasons for the late filing, observing that they had had ample time (over 1.5 years) to file suitable evidence. However, see also T 23/17 (opponent's argument that new documents had been filed in response to experimental data produced by the patent proprietor in its reply 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. It pointed out that, by acting in this way, the appellant had prevented the respondent from reacting to the attack during the opposition proceedings and the opposition division from deciding on the matter.

For further cases 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 2112/16 (in which the board also noted that the amendments made in request 1A did not overcome the raised objections) and T 967/16 (no established "last chance" doctrine; see chapter V.A.4.5.10g)).

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 late filing of submissions was justified is a factor the boards have considered in exercising their discretion; see chapter V.A.4.5.10d) in particular.