In the above-mentioned decision, the Enlarged Board of Appeal dealt with the question of the extent to which evidence submitted after the filing date can be used to substantiate inventive step.

In the grant procedure before the European Patent Office, it is generally possible to submit evidence, in particular in the form of experimental test data, which can be used to credibly demonstrate an advantageous technical effect over the prior art found - and to substantiate an inventive step.

In recent years, however, it seems to have become successively more difficult to submit such data to prove inventive step. Moreover, an achievable technical effect cannot be credibly demonstrated solely with subsequently submitted data.

However, in the recent decision G 2/21, the Enlarged Board of Appeal of the EPO took the view that the question of the admissibility of subsequently filed evidence to substantiate the inventive step should be seen in the context of the principle of free evaluation of evidence by the EPO, which does not allow post-published evidence to be disregarded solely because it was submitted after the filing date (see 1st headnote of the decision).

In addition, the Enlarged Board of Appeal provides decision criteria to help decide whether or not post-published evidence can be used to support an asserted technical effect (see second headnote of the decision).

The two guiding principles of the decision read accordingly:

1. LS: The evidence submitted by a patent applicant or patentee to prove a technical effect used to establish the inventive step of the claimed subject-matter may not be disregarded merely because the evidence on which the effect is based was not published before the filing date of the patent in suit and was submitted after that date.
2. LS: A patent applicant or proprietor may rely on a technical effect on the question of inventive step if the skilled person, being aware of the common general state of knowledge and on the basis of the application filed, can deduce this effect as being comprised in the technical teaching and embodied in the same originally disclosed invention.