The EPO Enlarged Board of Appeal has now issued their decision on G2/21, a case which was intended to decide whether evidence submitted after the filing date could be used to support inventive step.


As we previously reported, in this case the Enlarged Board of Appeal were asked to consider three questions, namely:


  1. Should evidence showing an effect (i.e. new experimental data) be disregarded if it is not in the application as filed and the new evidence is the only evidence of any effect?
  2. If so, is this still the case if the effect is plausible based on information in the patent application or the common general knowledge?
  3. Or can the evidence be taken into account simply if there was no reason at the filing date to consider the technical effect implausible?


On the first question the Enlarged Board of Appeal has given a clear answer, namely that evidence submitted to prove a technical effect relied on for inventive step may not be disregarded solely because it was filed after the filing date.


This will of course be a relief to patentees everywhere! If the Enlarged Board had decided otherwise, it could have ruled out the possibility of filing comparative data to support an inventive step after the filing date, even if such data were necessary in response to a newly discovered prior art document.


The Enlarged Board has gone on to discuss the concept of plausibility. In their referring decision the original Board of Appeal suggested that there were two types of approach taken in previous cases, namely that

(i) data can be taken into account if an effect was plausible based on the application as filed (so-called ‘ab initio plausibility’), or

(ii) data can be taken into account if there would have been no reason to consider an effect implausible based on the application as filed (so-called ‘ab initio implausibility’)


However, after reviewing the case law the Enlarged Board have decided that these approaches are not in fact different, and have concluded that in all cases “the core issue rests with the question of what the skilled person, with the common general knowledge in mind, understands at the filing date from the application as originally filed as the technical teaching of the claimed invention.”


As a result, in its opinion the Enlarged Board has come to the conclusion that the concept of “plausibility” is not a distinctive legal concept, but instead “describes a generic catchword seized in the jurisprudence of the boards of appeal”.


In the opinion of the Enlarged Board, the relevant question is what the skilled person would understand at the filing date from the application as originally filed as the technical teaching of the claimed invention. Consequently, the technical effect being claimed at any stage of the proceedings needs to be “encompassed by” the technical teaching of the application as filed and “to embody the same invention”.


It remains to be seen what standards will be applied by the Boards of Appeal as to whether a given technical effect meets these requirements. In fact the Enlarged Board itself notes in its decision that this criterion could be considered somewhat abstract. However, given the Enlarged Board’s indication that none of the existing case law would have come to a different conclusion following the test set out in their decision, perhaps the outcome of this case in practical terms will have little impact beyond confirming that post-published data can be filed to support an inventive step. Whether or not the claimed effect will be acknowledged remains to be decided on a case-by-case basis. However, as a rule of thumb it seems likely that post-published data which show a new effect different to the underlying concept described in the application as filed might not be able to support an inventive step.




Finally, although its preliminary opinion suggested that the issue of sufficiency would not be considered, the Enlarged Board has in the end acknowledged that the concept of plausibility is highly relevant to sufficiency as well as inventive step. In relation to sufficiency they have noted that the existing case law supports the view that “the scope of reliance on post published evidence is much narrower under sufficiency of disclosure (Article 83 EPC) compared to the situation under inventive step (Article 56 EPC)”.


Consequently, the requirement for sufficiency to be acknowledged remains that the application as filed must contain some proof that the claimed effect would be achieved, particularly if the effect would not be credible in the absence of any data. In contrast to inventive step, the issue of sufficiency cannot be remedied by post-published evidence.