Posted: December 7th, 2021
EBA referral G 2/21 – post-published evidence and plausibility, reported by Dr. Klaus Reindl and Dr. Georg Anetsberger, Bardehle Pagenberg
With the decision T 116/18, questions were referred to the Enlarged Board of Appeal (EBA) of the EPO that may have a significant impact on patent filing strategies as well as oppositions. They relate to the requirement of “plausibility” of a technical effect based on an application as filed.
In many decisions of the Boards of Appeal (BoA) of the EPO, such plausibility was stipulated as a requirement for the use of evidence for a technical effect (e.g. experimental data), if the evidence was not public before the filing date of a patent application and only filed after its filing date (“post-published evidence”).
In the past, post-published evidence was relied upon in many cases, e.g. to demonstrate inventive step or sufficiency of disclosure. At the same time, this practice has also been quite controversial. For example, the BoA decision T 1329/04 ruled that post-published evidence for a certain technical effect can be taken into account only if the technical effect is already “plausible” from the application as filed.
In the later decision T 578/06, a more liberal approach was taken instead: Post-published evidence can be used unless, based on the application as filed, a technical effect is implausible. There have been many decisions both ways since then. On top of that, there were also decisions (e.g. T 31/18) that seemed to dismiss the concept of plausibility and instead argued that a lack of plausibility cannot prevent post-published evidence from being used. T 116/18 ultimately decided that this discrepancy pertains to a fundamental legal question of importance for many cases and thus requires attention by the EBA.
Specifically, in T 116/18, it was decisive, whether the opposed patent provided an inventive step (see reasons, ref. 11): “For inventive step, the respondent relied on, inter alia, post-published evidence D21 in support of a synergistic effect.” (see reasons, ref. 11.2). The Board determined that the question of inventive step crucially depended on post-published evidence (see reasons, ref. 12.6). The Board then outlined the “three diverging lines of case law from the boards regarding the circumstances under which the evidence can or cannot be taken into account” (see reasons, ref. 13.2) which the Board termed “ab initio plausibility” (see reasons, ref. 13.4), “ab initio implausibility” (see reasons, ref. 13.5), and “no plausibility” (see reasons, ref. 13.6):
Ab initio plausibility
According to this first line of case law, “post-published evidence can be taken into account only if, given the application as filed and the common general knowledge at the filing date, the skilled person would have had reason to assume the purported technical effect to be achieved” (see reasons, ref. 13.4). Here, the patent proprietor bears the burden of proof for establishing plausibility.
Ab initio implausibility
In accordance with this second line of case law, “post-published evidence can only be disregarded if the skilled person would have had legitimate reasons to doubt that the purported technical effect would have been achieved on the filing date of the patent in suit” (see reasons, ref. 13.5). In other words, “post-published evidence must always be taken into account if the purported technical effect is not implausible” (see reasons, ref. 13.5). It is an opponent who needs to demonstrate that a technical effect was implausible at the filing date of the patent application (see reasons, ref. 15).
This third line of case law “seems to reject the concept of plausibility altogether” (see reasons, ref. 13.6). According to this line of case law, the concept of plausibility is incompatible with the assessment of inventive step according to the problem-solution approach.
The Board further noted that “ab initio plausibility” and “no plausibility” are “two extreme positions” (see reasons, ref. 13.7.1):
A strict application of “ab initio plausibility” may result in patents only “for embodiments for which experimental data or other substantiation is contained in the application as filed that makes the effect invoked for inventive step plausible for these embodiments” (see reasons, ref. 13.7.1). Further, “the patent proprietor would be barred from providing any evidence” in support of a reformulated technical problem, e.g. in case fresh prior art is cited during opposition proceedings. “This would mean a basically insurmountable hurdle for patentability once an opponent invokes a new closest prior-art document in opposition proceedings” (see reasons, ref. 13.7.2). The Board continued that “such an approach would go against decades of case law which has allowed the reformulation of the technical problem in view of new closest prior-art documents and the reliance on post-published evidence in support of the newly formulated problem” (see reasons, ref. 13.7.2).
On the other hand, if “no plausibility” was applied, “a patent applicant could claim whatever it thinks might possibly be proven later to bring about a purported technical effect. This would give rise to what is often referred to in the case law as “speculative patenting” or “armchair inventions” where a monopoly is conferred to a patent applicant for mere speculation rather than a true invention” (see reasons, ref. 13.7.1).
According to the Board, the “ab initio implausibility” may “lie somewhere between these two extreme lines of case law” (see reasons, ref. 13.7.1).
Finally, the Board also questioned whether the concept of plausibility is compatible at all with the “principle of free evaluation of evidence” (see reasons, ref. 13.7.3). In particular, it was questioned what legal basis could prevent “the patent proprietor from relying on a particular type of evidence of a fact relevant to the outcome of the proceedings” and “on what basis a board would be prohibited from taking into account evidence it finds convincing and decisive”.
Based on the above, the Board formulated the following three questions for referral to the EBA. Therein, the Board limited its questions to the case decisive use of post-published evidence for inventive step discussions, excluding questions as to sufficiency of disclosure:
“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)?”
It now remains to be seen, which direction the EBoA will go and whether it will provide specific guidance to applicants or leave it to the specific circumstances of each case to which extent post-published evidence may be considered (e.g., if question 1 is answered with a “no”).
In any case, its answers may have a big impact not only on the assessment of inventive step but also on the BoA’s practice for assessing sufficiency of disclosure, particularly for chemical and pharmaceutical inventions which often make it difficult to predict a technical effect without experimental data. Filing strategies may need to be revisited accordingly.