Patentability is closely related to the provision of a technical solution to a technical problem and occasionally the Applicant may have to demonstrate the plausibility of a particular technical effect in support of an inventive step or of sufficiency.
This may require providing documents after filing, however the rules regarding the circumstances under which a supporting evidence can or cannot be used to support plausibility lacks consistency.
A recent EPO case (T0116/18) illustrates how supporting evidence provided after filing may affect the outcome of a patent during opposition proceedings.
Background
Patent EP2484209(B1) relates to an insecticide composition that includes thiamethoxam and one or not less than two kinds of compounds selected from a compound represented by a specific formula.
The patent provides examples of insect pests which can be controlled with the insecticide composition including Spodoptera litura, Plutella xylostella and Chilo suppressalis. The patent also determines the activities (death rate) of the individual insecticides observed when a number of insects is exposed to the insecticide. An expected activity for the joint use of both insecticides corresponding to a purely additive effect of both insecticides is then calculated. Depending on the determined activity of the combination of both insecticides being above or below this expected value, the insecticides act synergistically or antagonistically.
The patent was then opposed on various ground. The opponent submitted two experimental reports intended to show that the combination of thiamethoxam and chlorantraniliprole does not act synergistically. The patent proprietor submitted additional test data (documents D21 and D22) to prove a synergistic effect from combining thiamethoxam with compounds according to the formula of claim 1.
The opposition division rejected the opposition holding that the objective technical problem was the provision of an insecticide combination whose insecticides acted synergistically against Chilo suppressalis. The solution to this problem was not obvious because synergism per se was unpredictable. The opponent (Appellant) appealed this decision and requesting that documents (D21 and D22) should not be taken into account to prove the alleged synergy.
The Board of Appeal then assessed whether D21 was relevant for inventive step and concluded that the outcome of the case depended on whether the post‑published data in D21 which where the only proof of a synergistic effect against Chilo suppresalis could be taken into account.
Diverging Case Law
Proceedings before the EPO are conducted in accordance with the principle of the “free evaluation of evidence” which means that there are no firm rules according to which certain types of evidence are, or are not, convincing. The question of whether a fact can be regarded as proven must be assessed on the basis of all the relevant evidence. Over the years the acceptance or rejection of post evidence in support of plausibility has been assessed following three different approaches.
In a first approach referred to as “Ab initio plausibility” standard, post evidence can be considered only if the skilled person would have had reason to assume the supposed technical effect to be achieved. This is considering the information provided in the application as filed, for instance experimental data, and the common general knowledge at the filing date.
In a second approach referred to as “Ab initio implausibility” standard, 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 this case post-published evidence must be considered if the supposed technical effect is not implausible.
In a third approach referred to as “No plausibility” standard, a lack of plausibility of a technical effect based on the absence of evidence in the patent application is not considered a sufficient reason to disregard future information filed later to prove that effect. The basis for this standard is that rejecting such information would be inconsistent with the problem-solution approach that requires defining an objective technical problem which may evolve during examination depending on the closest prior art document not necessarily known at the time of filing the application.
The questions referred to the Enlarged Board of Appeal G2/21
In view of this apparent lack of consistency the Board of Appeal has referred the following questions (wording simplified for the purpose of this article):
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…
- Should an exception to the principle of free evaluation of evidence …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?
- 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)?
- 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)?
Conclusion
Issues of plausibility tend to occur more frequently in the field of chemistry and life science, as extensive experimental studies may be required to demonstrate a particular effect (for instance of a specific substance over a particular range). However issues of plausibility may still occur in other technical fields.
The answer to the questions referred above are expected later during the year, and should bring some welcome clarity; we will keep you posted!
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