a) Time of filing – whether the new submissions should have been filed earlier 

(i) Duty of the party to properly conduct the proceedings 

In T 1014/17 the board considered that, in the circumstances, the appellant had already had ample opportunity to revise its position on the clarity of claim 1 and raise appropriate objections, and could have done so in its grounds of appeal at the latest. What was more, it had had a responsibility to do so in view of what was required for properly conducted proceedings, including the duty on the parties to file all facts, evidence, arguments and requests as early and as completely as possible (Art. 12(2) RPBA), and also for reasons of fairness towards the respondent (patent proprietor), who had to be able to see as early as possible to what extent its patent was being challenged and on what grounds. The board refused to admit the objection under Art. 13(1) RPBA and Art. 13(1) and (3) RPBA 2007.

(ii) Response to new evidence submitted by the patent proprietor 

In T 23/17 the board exercised its discretion under Art. 13(1) RPBA and held plausible and understandable the argument made by the appellant (opponent) that the new documents (filed after the statement of grounds of appeal but before the notification of the summons to oral proceedings) had been filed in response to the experimental data presented by the respondent (patent proprietor) in its reply to the appeal and so, as Art. 13(1) RPBA, put it, "to resolve the issues which were admissibly raised by another party in the appeal proceedings". The board could not see that there had been any reason to file these documents at an earlier stage of the proceedings.

In T 446/16 too, the appellant (opponent) had filed experimental report D35 after its grounds of appeal but before the summons with a view to rebutting the experimental results in D33, which the respondent (patent proprietor) had filed with its reply. The board accepted the reasoning that this response to D33 could not have been filed earlier, finding that the appellant could not be denied an opportunity to cast doubt on the results in D33 in this way.

However, see also T 2688/16 for an example of a case in which a board refused to admit experimental results owing to a lack of adequate reasons for their late filing (see chapter V.A.4.4.4b)).

In T 1759/17 the appellant (opponent) filed new documents in direct response to the respondent's reply to the grounds of appeal and in particular to the new evidence filed by the respondent. Since there were no objections from the respondent (patent proprietor) against admission of these documents, the board decided to admit them into the proceedings.

(iii) Response to new claim requests filed with the reply after opposition had been rejected 

In T 1038/18 the respondent (proprietor) filed new requests with its reply to the statement of grounds of appeal. In its rejoinder the appellant (opponent) submitted for the first time during the proceedings that the priority of the patent was not validly claimed and that consequently claim 1 of auxiliary request 2 did not involve an inventive step over D1 and D3, the latter representing in view of the invalid priority claim state of the art within the meaning of Art. 54(2) EPC. However, auxiliary request 2 corresponded to the claims of a request submitted already during first-instance proceedings. The respondent argued that the new attack should have been presented earlier, but the board did not agree. It pointed out that the opposition had been rejected by the opposition division and hence the appellant was only required in the statement of grounds of appeal to substantiate why they considered non-convincing the reasons given by the opposition division in respect of the patent as granted. The question of the validity of the priority and of the status of document D3 as state of the art only became pertinent when subsequently the respondent, in reply to the statement of grounds of appeal, filed the amended claims of auxiliary request 2.

(iv) Need to reply to proprietor’s detailed case in the grounds of appeal 

In T 329/16 the board referred to Art. 12(3) RPBA and concluded that the onus had been on the opponents to make a substantiated case in support of its inventive-step objections in its reply, even though the opposition decision had found in its decision that the subject-matter of claim 1 of auxiliary request 1 lacked novelty. Given that the patent proprietor had made a detailed case in support of the subject-matter's novelty in its grounds of appeal, the opponent could not rely on the board's reaching the same conclusion as the opposition division.

(v) New lines of attack based on documents submitted during first-instance proceedings 

In T 256/17 the board had to decide whether to admit two new lines of attack submitted against claim 1 of the patent on the basis of a lack of inventive step which the appellant (opponent) had filed in response to the respondent's reply. Both lines of attack were based on documents submitted during the first-instance proceedings, but one of them combined for the first time two documents previously discussed as the closest prior art and the other, starting from a known combination, argued on the basis of a different technical problem. The appellant gave no reasons for first raising these objections after having filed the statement of grounds of appeal, and the board could no reason for this either. It pointed out that, by acting 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. With the late submission the appellant had confronted the board and the respondent with a fresh case, which was contrary to the very aim of appeal proceedings (Art. 12(2) RPBA). The board thus decided to exercise its discretion not to admit the new lines of attack under Art. 12(2), (4) RPBA 2007, Art. 25(2) RPBA and Art. 13(1) RPBA, Art. 25(1) RPBA.

(vi) Defence which should have been presented before the opposition division 

In T 1303/18 the board did not admit into the proceedings the appellant’s (proprietor’s) defence (raised for the first time after the filing of the grounds of appeal and the replies) relying on entitlement to partial priority. The appellant had argued that the subject-matter of claim 1 as granted should at least be entitled to partial priority from D49 in accordance with decision G 1/15. The board observed that an objection as to the validity of the priority claimed from D49 had already been raised by the respondents in their notices of opposition. Decision G 1/15 had been published in the Official Journal of the EPO before the oral proceedings were held before the opposition division. Therefore, the appellant's defence claiming a right to partial priority could and should have been included at the latest in the statement of grounds of appeal. Moreover, the new defence was not merely a presentation of a new argument pertaining to the interpretation of law but comprised a new allegation of fact. The board decided not to admit it into the proceedings, as the required new factual assessment would have been complex and the appellant had provided no justification for this late amendment.

(vii) Common general knowledge 

In T 2741/19 the board did not find the appellant’s (opponent’s) justification convincing that the document was only found during the preparation of the opposition against a patent originating from a divisional application filed in relation to the present patent. The board pointed out that the document was part of the public domain. Nor did the board accept the appellant’s argument that the document was submitted as evidence for the skilled person’s common general knowledge at the time. Even if it were common general knowledge, this did not mean that it could be filed at any time of the proceedings. Evidence of common general knowledge could be filed at a later stage only if it served to back up argumentation that has already been put forward.

In T 1333/20 the board held that the respondent (opponent) could and should have submitted its complete case, including the alleged proof of common general knowledge supporting its insufficiency of disclosure objections against the patent as granted, at least when forming its appeal case with its reply to the statement setting out the grounds of appeal. The appellant had already focused on insufficient evidence as regards Art. 100(b) EPC in the opposition proceedings and in the statement setting out the grounds of appeal.

In T 1417/18, by contrast, D10, a textbook referred to by the appellant within the time limit set by the board in its communication under R. 100(2) EPC, was taken into account. D10 had already been submitted by the opponent (subsequent appellant) in the opposition proceedings, but had not been admitted. The board held that D10 was relevant for assessing common general knowledge. It also took into account that both parties were already familiar with D10. The fact that D10 had not been admitted in the first-instance proceedings was considered immaterial.

(viii) Developments in parallel proceedings 

In T 1038/19, in exercise of its discretion under Art. 13(1) RPBA, the board admitted a new objection of added subject-matter of claim 1 of the main request. The appellant (opponent) had raised this objection shortly after a similar issue had been decided in its favour in parallel proceedings (T 1773/18). The board saw this as justified, especially in view of the developments in the parallel appeal case. It also took into account that the other parties to the proceedings had had sufficient time to consider the objection.

A counter-example is T 1808/21. In this case presentation slides (D26) and a compilation of alleged facts (D27), which were subject of parallel pending UK proceedings, were submitted by appellants 2 and 3 only after filing their respective grounds of appeal. The appellants argued that, since this evidence had not yet been referred to at trial in the English proceedings, it was not possible to file it at an earlier stage in the appeal proceedings. The board however pointed to the possibilities of seeking consent from the patent proprietor or getting permission from the English court. In view of this, the board was convinced that there had been no legal obstacles and that it was rather the choice of the appellants not to submit these documents at an earlier stage. Therefore the board did not admit D26 and D27 into the appeal proceedings.

(ix) Late discovery of documents 

In T 603/21, after filing its statement of grounds of appeal (but before notification of the summons to oral proceedings), the appellant (opponent) made new attacks on inventive step, based on, among other things, two new documents. It argued that the documents had only recently come to light by chance during research into another case and were prima facie relevant. The board stressed, however, that the chance discovery was not sufficient to justify the late filing, as generally admitting such changes would allow the arbitrary extension of the subject of the proceedings beyond that of the opposition proceedings, and thus run counter to the primary object of the appeal proceedings as set out in Art. 12(2) RPBA. In particular, this would undermine the requirement of Art. 12(6) RPBA, and failure by one of the parties to comply with it would be detrimental to the opposing side. Similarly T 1684/17 (summarised in chapter V.A.4.4.6d) and T 2741/19 (the fact that the document could not be easily found was not considered a justification for late filing). However, see also T 1213/19 date: 2022-09-23 (also summarised in chapter V.A.4.4.6c) (ii).

However, see also T 463/19, in which, even at the third level of the convergent approach, the board admitted a late-filed document that was objectively difficult to find, had undoubtedly not been withheld intentionally, belonged prima facie to the state of the art and was prima facie very relevant. See chapter V.A.4.5.5m).

(x) New document originating from the patent proprietor submitted by the appellant-opponent 

In T 533/17 the appellant (opponent) argued that a poster (D19) and two related documents, filed after its grounds of appeal, should be considered since the respondent (patent proprietor) had apparently concealed this earlier own publication. The board, however, noted that R. 42(1)(b) EPC did not put a stringent obligation on applicants to acknowledge prior art known to them at the time of filing their application. Therefore, the failure to acknowledge D19 in the patent in suit was not a sufficient reason for admitting this document into the appeal proceedings. Moreover, the appellant had not provided a convincing justification of why it had not been possible to find D19 when preparing this case at the opposition stage. The new documents were therefore not considered, in accordance with Art. 13(1) and 25(3) RPBA.

(xi) Public prior use 

In T 552/18 the board did not admit further evidence of a public prior use filed in reply to its communication under Art. 15(1) RPBA 2007 for the following reasons: These documents had been submitted at a very late stage of the proceedings and raised new questions. Although appellant 2 (opponent) had provided reasons why the documents had only been retrieved when they were, the board considered that there was no justification why they could not have been retrieved earlier if sufficient effort had been made. The board also held that the admission of these documents would go against the interests of procedural economy as laid down in Art. 13(1) RPBA. Moreover, the documents presented did not enable the issues raised to be resolved, as was required by Art. 13(1) RPBA. The board also underlined that these issues' pertinence had already been known in the opposition proceedings.

Likewise in T 1117/16 the board considered it immaterial that the appellant had only actually become aware of the alleged public prior use – in this case by a third party – a few months after the filing of the statement of grounds of appeal. In particular, it took into account that the search for possible citations is the responsibility of the opponent. The fact that it did not discover a state of the art in time did not justify disregarding either the requirement of procedural economy or the need to act fairly towards the other parties. The board held that other criteria for the exercise of discretion mentioned in Art. 13(1), fourth sentence, RPBA also precluded admission to proceedings (see the summary in chapter V.A.4.4.6 b).

By contrast, in T 34/18 the board considered the filing of new pieces of evidence of prior use (minutes of a hearing before a technical section of the Austrian Patent Office and a witness's written statements), which were intended to prove the existence of an obligation of confidentiality, to be admissible under Art. 13(1) RPBA. In particular, the board took into account that the opposition division had assumed there was no such agreement, that the evidence was therefore prima facie relevant, that its admittance did not appear to be detrimental to procedural economy and that the appellant had convincingly argued that the new evidence could not have been provided earlier.