Enlarged Board of Appeal Referral on Plausibility The concept of plausibility goes to the heart of the fundamental principle that a monopoly for an invention can only be awarded in return for a disclosure of that invention.
The Boards of Appeal of the European Patent Office (EPO) and the courts of the United Kingdom have expressed the significance of plausibility as follows:
rendered plausible in the application as originally filed, otherwise postfiling data cannot be considered in support of a sufficiency of disclosure or inventive step.
“The definition of an invention as being a contribution to the art, i.e., as solving a technical problem and not merely putting forward one, requires that it is at least made plausible by the disclosure in the application that its teaching solves indeed the problem it purports to solve.” ¹
However, in a recent EPO Board of Appeal case (T 116/18) it was suggested that the Boards of Appeal are not completely consistent on this issue. In particular, it would appear that some Boards of Appeal consider that the requirement for the technical effect of a claimed invention to be rendered plausible in the application as filed is incompatible with the problem solution approach for assessing inventive step.
“Plausibility is to exclude speculative patents, based on mere assertion, where there is no real reason to suppose that the assertion is true” ²
is to “ Plausibility exclude speculative patents, based on mere assertion, where there is no real reason to suppose that the assertion is true.
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A lack of plausibility is not, in itself, a ground for invalidity of a patent according to the European Patent Convention or the UK Patents Act 1977. Rather, plausibility is usually raised in the context of sufficiency of disclosure or inventive step. The case law concerning plausibility appeared to be fairly settled, with a series of EPO Board of Appeal decisions finding that an invention must be
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T 116/18 concerned European Patent No. 2484209, which was granted with claims directed to an insecticide comprising thiamethoxam and one or more compounds defined by a formula 1a encompassing a large number of possible compounds. The difference between the claimed subject-matter and the closest prior art was identified as the selection of the compounds to be combined, with the selected combination purported to have a synergistic effect. The patent included examples testing the interaction between thiamethoxam and various compounds of formula 1a, but no evidence of synergy was provided. During appeal proceedings, the patentee provided post-published documents which contained data showing synergy between thiamethoxam and compounds of formula 1a. In response, the opponent, following what appeared
to be the established EPO case law, argued that the synergy between thiamethoxam and compounds of formula 1a had not been rendered plausible in the application as filed and so the post-published documents should not be taken into account. The Board of Appeal noted that the question of whether or not the post-published evidence could be considered was decisive for the question of whether or not the claimed subject-matter involved an inventive step. Then, somewhat surprisingly, the Board of Appeal identified conflicting earlier Board of Appeal decisions on the question of admissibility of post-published evidence to support inventive step. The Board of Appeal referred to the requirement for a technical effect to be rendered plausible in the application as filed as “ab initio plausibility” and legal basis for this requirement was identified in a number of earlier decisions (including T 488/16, T 1329/04, and T 433/05). However, they also referred to conflicting decisions in which the criterion for ab-initio plausibility had not been applied and where Boards of Appeal had found that a lack of ab initio plausibility was not a reason to disregard post-published evidence (for example, decisions T 2371/13 and T 31/18). These Boards of Appeal were of the opinion that the requirement for a technical effect to be plausibly demonstrated in application as filed was incompatible with the problem solution approach
