In T 49/85 the board stated that a reference filed by an opponent for the first time with its statement of grounds was not submitted in due time unless representing the effective counter evidence to a newly emphasised reason given in the decision (see also T 172/85 and T 561/89). It is however within the discretion of a board of appeal pursuant to Art. 114(1) EPC to admit such a document into the proceedings in view of its relevance (T 339/08). The same applied if the party reacted to its opponent's submission, e.g. in T 705/90, where documents I to N were cited by the appellant in its observations in support of an argument presented in response to the respondent's statement of grounds. Similarly, in T 238/92 the board of appeal did not consider a document presented for the first time with the statement of grounds of appeal as "late-filed", since it served as the first evidence of a feature considered in the contested decision as essential for the assessment of inventive step (see also T 117/92).
In T 927/04 the board stated that, it was legitimate for a party who had lost in opposition proceedings to try to improve its position in appeal by filling a presumed missing link, as in the case in point, with respect to the issue of prior use. Taking further into account the fact that the documents had been submitted at the earliest possible moment by the appellant, namely at the beginning of the appeal proceedings, the filing of these documents could thus not represent an abuse of proceedings. Consequently, the board decided to introduce these documents into the proceedings.
In T 1380/04 D16 was submitted for the first time with the statement of grounds. In the board's view, the submission of D16 along with the statement of grounds was a justified reaction to the opposition division's decision. However, this in itself was not enough to justify admitting the document into the proceedings. The document would also have to relate more to inventive step prima facie than any other document already in the proceedings. The board concluded that D16 was so relevant to the issue of inventive step that it had to be considered in the rest of the proceedings.
In T 1146/06 the appellant filed D5 with the statement of grounds of appeal and in reaction to the reasons of the decision under appeal, according to which the opposition division rejected the opposition because it arrived at a conclusion adverse to the appellant on the basis of the prior art then on file. The board found D5 prima facie relevant and nothing in the file indicated that D5 could have been filed earlier. Therefore, the board admitted D5 into the appeal proceedings.
In T 666/09, the board agreed with the appellants that the comparative study filed with the statement of grounds of appeal was a direct response to the opposition division's decision. The appellants had filed it in an attempt to rebut the findings of deficiencies in that decision and had done so without delay at the earliest possible opportunity in the appeal proceedings.