The Enlarged Board of Appeal formally seized of a referral concerning the “plausibility” criterion in the assessment of inventive step

As previously mentioned here, this referral relates to the appeal case T 116/18, which concerns the opposition of European Patent No. 2 484 209 relating to an insecticide composition comprising thiamethoxam and at least a compound of “formula 1a”. The technical effect relied upon for inventive step in this case was the synergy between both compounds. While the patentee referred to post-published data to support this synergy, the opponent argued that said post-published data should be disregarded considering that the technical effect was not made plausible in the application as filed (lack of “ab initio plausibility”).

Considering the divergence in the case law on these issues, the TBA No. 3.3.02 has now formally issued its referral decision with the following questions to be referred to the EBA:

“If for acknowledgement of inventive step the patent proprietor relies on a technical effect and has submitted evidence, such as experimental data, to prove such an effect, this evidence not having been public before the filing date of the patent in suit and having been filed after that date (post-published evidence) :

1.  Should an exception to the principle of free evaluation of evidence (see e.g. G 3/97, Reasons 5, and G 1/12, Reasons 31) be accepted in that post-published evidence must be disregarded on the ground that the proof of the effect rests exclusively on the post-published evidence?
2.  If the answer is yes (the post-published evidence must be disregarded if the proof of the effect rests exclusively on this evidence), can the post-published evidence be taken into consideration if, based on the information in the patent application in suit or the common general knowledge, the skilled person at the filing date of the patent application in suit would have considered the effect plausible (ab initio plausibility)?
3. If the answer to the first question is yes (the post-published evidence must be disregarded if the proof of the effect rests exclusively on this evidence), can the post-published evidence be taken into consideration if, based on the information in the patent application in suit or the common general knowledge, the skilled person at the filing date of the patent application in suit would have seen no reason to consider the effect implausible (ab initio implausibility)?”

In the conclusion of its referral decision, the TBA No. 3.3.02 notably pointed out that: 

“(…) it is evident that a referral of questions to the Enlarged Board of Appeal is needed, both to ensure uniform application of the law and because points of law of fundamental importance have arisen. The three referral questions made in the order of the present decision relate to the three lines of case law discussed above, namely whether any plausibility standard can be applied at all (first referral question) and, if so, whether an ab initio plausibility standard (second referral question) or an ab initio implausibility standard (third referral question) is to be applied.”

We will comment further on this decision and its consequences in a later post.