Plausibility: Insights from the G 2/21 preliminary opinion

The EPO’s Enlarged Board of Appeal (EBA) referral G 2/21 will hopefully clarify the circumstances under which a purported technical effect can be relied on for inventive step and supported by post-published evidence. The recently issued preliminary opinion, which is non-binding, hints towards favouring the ‘ab initio implausibility’ standard.

Background

As we reported here, the Technical Board of Appeal 3.3.02 referred three questions of law to the EBA:

  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?
  1. 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)?
  1. 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)?

Scope of the Referral

Significantly, the EBA notes in their preliminary opinion that the scope of the referral is limited to plausibility and post-published evidence in the context of assessing inventive step and not sufficiency of disclosure (paragraph 14).

Preliminary Opinion on the Questions Referred

Question 1

The EBA considers that the principle of free evaluation of evidence prohibits evidence being disregarded if “it is relied upon by a party in support of an inference which is challenged and is decisive for the final decision” (paragraph 12). This indicates that post-published evidence, such as experimental data, submitted in support of an alleged technical effect which is relied upon for inventive step cannot simply be disregarded, even when submitted as exclusive support for the technical effect.

In particular, the EBA highlights that “disregarding such evidence as a matter of principle would deprive the party submitting and relying on such evidence of a basic legal procedural right” (paragraphs 11-12).

Despite answering “no”, the EBA acknowledges the need to provide guidance on questions 2 and 3 (paragraph 13), indicating that there is nonetheless a hurdle to rely upon post-published evidence to support a purported technical effect.

Questions 2 and 3

The preliminary opinion reveals an unwillingness of the EBA to adopt the terms “plausibility” and “implausibility”. Instead, the EBA considers that a technical effect relied upon for inventive step needs:

  • “to be encompassed by [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] and to embody the same invention.” (paragraph 15); and
  • “to be assessed as to whether the skilled person, having the common general knowledge in mind, would have had any significant reason to doubt it [on the basis of the application documents and this technical teaching].” (paragraph 16).

The requirement (b) appears to set the threshold at a lack of “ab initio implausibility”, i.e. provided that the skilled person would not have significant reason to doubt the technical effect at the filing date in view of their common general knowledge and the teaching of the application as filed the post-published evidence can be taken into account.

Meanwhile, (a) appears to be a baseline requirement that the technical effect is “encompassed by [the technical teaching of the application at the filing date]” and “embod[ies] the same invention”. Yet, no further explanation of these criteria is provided in the preliminary opinion. Therefore, it remains to be seen whether a technical effect that is not explicitly identified in the application as filed can form the basis of an inventive step.

Linking these requirements to the use of post-published evidence, the EBA confirms that:

“the reliance on post-published evidence, such as experimental data, for the purported technical effect would seem to serve as a potential source for a deciding body to conclude whether or not it is convinced of said technical effect when deciding on the inventiveness of the claimed subject-matter. However, whether such evidence could also successfully be relied upon in the event that the skilled person, on the basis of the application as originally filed together with the common general knowledge, had significant doubts in respect of the purported technical effect, appears questionable.” (paragraphs 17-18)

Thus, the preliminary opinion seems to endorse the approach to file early and add supporting experimental data later, provided that the data supports a technical effect that was not implausible at the filing date. This is particularly significant in the fields of biotechnology, life sciences and chemistry, wherein technical effects that are more than speculation at the filing date but nevertheless require later supportive data, such as comparative data, are common.

Summary

The preliminary opinion in G 2/21 hints that a low hurdle must be applied for a purported technical effect to be supported by post-published data, namely that the skilled person at the filing date had no significant reason to doubt the technical effect (a lack of ‘ab initio implausibility’).  Note this communication is non-binding and further submissions are expected before the oral proceedings scheduled for 24 November 2022.

We await the EBA’s final decision, which is expected in mid-2023.