EPO Enlarged Board of Appeal Issues Preliminary Opinion in Plausibility Referral G2/21

We reported in August 2021 that the EPO’s Enlarged Board of Appeal (EBA) would be considering the doctrine of plausibility at the EPO. We further reported in October 2021 the questions that were referred to the EBA by the Technical Board of Appeal considering the underlying decision and which form the basis of referral G2/21.

The questions as referred are somewhat unwieldy, but may be summarised as:

If a patent proprietor submits post-published evidence, such as experimental data, to prove a technical effect relied on for inventive step…

1.  Must post-published evidence be disregarded if the proof of the effect rests exclusively on the post-published evidence?

2. If the answer to (1) is yes, then can the post-published evidence be taken into consideration if the skilled person would have considered the effect plausible based on the information in the patent application and common general knowledge?

3. If the answer to (1) is yes, then can the post-published evidence be taken into consideration if the skilled person would not have considered the effect implausible based on the information in the patent application and common general knowledge?

Since our previous report, the EBA has announced that oral proceedings will be held on 24 November 2022. In advance of the hearing, the EBA has recently issued a non-binding preliminary opinion setting out its initial views on the admissibility of the referral and the approach that it envisages adopting. The overall approach adopted by the Board is likely to be encouraging to patentees, but may be less favourably received by opponents.

Regarding question 1, it is unsurprising that the EBA has indicated that post-published evidence should not, as a matter of principle, be disregarded. The principle of free evaluation of evidence at the EPO is a long-standing doctrine and any suggestion that post-published evidence “must” be disregarded would represent a major departure from the EPO’s established position.

In relation to questions 2 and 3, the approach favoured by the EBA seems to be a fairly lenient one: essentially asking only whether the skilled person

“would have had any significant reason to doubt [the technical effect].”

In the absence of such doubts, the EBA suggests that post-published evidence would be available to a tribunal in deciding on inventive step. However, the EBA considers it “questionable” whether such reliance can be successful when significant doubts exist.

The EBA’s opinion is only preliminary, and may alter in view of further submissions from the parties, including at the hearing itself. However, the EBA’s current views clearly favour a broadly lenient approach to the use of post-published evidence, which will be welcomed by applicants and patentees. The EBA seems inclined more towards the “allowable if not implausible” test rather than the more restrictive “allowable only if plausible” test.

For those concerned about the possibility of wholly speculative third party applications, there is some comfort: the EBA makes reference to the basic principle that the technical effect relied upon should be identified as embodying the “same invention” as that originally disclosed, suggesting that such speculative applications will not be allowed.

With a hearing date in November, we expect the EBA’s written decision to issue in spring/early summer of 2023. We will continue to report developments as they occur.