Plausibility at the EPO - Enlarged Board of Appeal decision G2/21

The long-awaited Enlarged Board of Appeal decision G2/21 has finally been issued. It confirms that evidence submitted in support of inventive step cannot be disregarded solely on the ground that such evidence had not been public before the filing date and was only filed after that date.

The background to this Decision and the referral to the EBA is explained in our earlier article "Plausibility - EPO stays proceedings in view of Enlarged Board Referral". In essence, the Board was asked to consider whether data supporting inventive step could be taken into account if it was only provided after the application had been filed.

Interestingly, the EBA dismisses the concept of "plausibility" as being a term that "does not amount to a distinctive legal concept or a specific patent law requirement under the EPC". However, while accepting that post-filed evidence submitted to prove a purported technical effect relied upon may be taken into account in assessing inventive step, this was only the case where:

"the skilled person, having the common general knowledge in mind, and based on the application as originally filed, would derive said effect as being encompassed by the technical teaching and embodied by the same originally disclosed invention." [emphasis added]

The Decision does not, however, provide any guidance on what this means and so it remains to be seen how this will be applied in practice.

Regarding sufficiency, the EBA specifically referenced pharmaceutical patents and stated that experimental evidence of a therapeutic effect needed to be present in the application as filed, particularly if, in the absence of such data, the therapeutic effect was not credible from the application as filed. Otherwise, then there would be a finding of insufficiency that could not be remedied by post-filed data.