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T 0116/18 - a new plausibility threshold for post-filing data?

T 0116/18 - a new plausibility threshold for post-filing data?

European Industry news 15/07/2021

At the European Patent Office (EPO), the Board of Appeal in T 0116/18 appears set to refer to the Enlarged Board of Appeal (EBA) the question of whether, for the acknowledgement of inventive step, a technical effect must be made plausible from the disclosure of an application as filed (so called “ab initio plausibility”). In particular, the referral aims to clarify whether post-published data can be used in the situation where the proof of the effect is exclusively provided by such post-published data.

It is established practise before the EPO that an applicant may use post-filed data to support the presence of an inventive step. However, in 2005, Board of Appeal Decision No. T 1329/04 introduced the requirement that the technical effect of an invention must at least be made “plausible” from the disclosure of the application as filed. Therefore, even if supplementary post-published evidence might also be taken into consideration, it cannot serve as the sole basis for establishing that the claimed invention solves the problem it purports to solve.

In the present case of T 0116/18, the opposed Patent related to an insecticide composition comprising thiamethoxam and a second compound defined by a particular Markush formula. At first instance, the Opposition Division ruled that the combination of the compounds was distinguished from the prior art in that both compounds at least required selection from the broader teachings of a particular document.

Syngenta (the Opponent) argued that no such technical effect was achieved by the distinguishing features, whereas the Proprietor argued that the effect of this distinguishing feature is a synergism between the compounds and submitted post-filing experimental data to support this assertion. The Opponent contended that the effect of a synergy had not been made “plausible” in the application as filed, therefore not meeting the test set by T 1329/04 and so the post-filing data should be disregarded.

Upon consideration of whether the post-filing data ought to be considered, the Board noted a divergence of the case law in this respect. One line of case law, including T 1329/04, points to the precondition for taking into account post-published evidence to demonstrate a certain effect is that it was already plausible at the filing date that the effect could be obtained (see also, for example, T 488/16 and T 433/05).

However, as pointed out by the Board, the legal basis for such a criterion has been questioned and, in fact, has not been applied in several cases. In this other line of case law, for instance, in T1422/12, the Board allowed the consideration of post-published data because the effect in question, despite not being mentioned in the application as filed, concerned the same field of use and did not change the character of the invention. In T 2371/13, the Board went even further and stated that a lack of ab initio plausibility was not sufficient reasoning for disregarding post published evidence, because disregarding such evidence was incompatible with the problem-solution approach. In T 31/18, the Board ruled that an effect does not necessarily need to be originally supported by experimental evidence so long as it is “at least derivable” from the application as filed.

These Decisions undoubtedly conflict with the likes of T 488/16, T 1329/04 and T 433/05. In view of this apparent disparity in the case law, the Board noted that a further question arises: That is, if one accepts that an effect must be plausible from an application as filed, whom does the burden of proof fall upon? Is it for the proprietor to show ab initio plausibility or is it for the opponent to show ab initio implausibility?

In view of the above findings, the Board of T 0116/18 set out several provisionally formulated questions during the Oral Proceedings that appear likely to reflect the questions of law to be referred to the EBA. These were presented as follows:

If for acknowledgement of inventive step the patent proprietor relies on a technical effect and has submitted data or other evidence to prove such effect, such data or other evidence having been generated only after the priority or filing date of the patent (post-published data):

  1. Should an exception to the principle of free evaluation of evidence (see e.g. G 1/12 reasons 31) be accepted in that the post-published data must be disregarded on the ground that the proof of the effect rests exclusively on such post-published data?
  2. If the answer is yes (post published data must be disregarded if the proof of the effect rests exclusively on these data): can post-published data be taken into consideration if based on the information in the patent application the skilled person at the relevant date would have considered the effect plausible (ab initio plausibility)?
  3. If the answer to the first question is yes (post published data must be disregarded if the proof of the effect rests exclusively on these data): can post-published data be taken into consideration if based on the information in the patent application the skilled person at the relevant date would have seen no reason to consider the effect implausible (ab initio implausibility)?

The decision of the EBA may have significant consequences for the timing of filing and content of patent applications, particularly those in the life science and biotechnology sectors. Patent applicants have to balance the advantages of securing an early filing date with the risk of including less data to rely upon to support a particular technical effect. The alternative is to include greater quantities of data as it becomes available but inevitably file the application later and risk facing additional prior art.

In many respects, it seems improbable that the EBA will freely lower the threshold of plausibility and there is a possibility that any EBA decision may restrict the use of post-filing data further. If so, applicants will need to be mindful of the quantity of data committed to the application before filing – too little and an application may be fatally flawed. At the same time, applicants must also think carefully as to how the invention, and the problem it purports to solve, is to be framed in order to extract the greatest value from the data that is ultimately included in the application.

We look forward to providing further commentary once the referral has been published. In the meantime, please contact Charlotte Watkins at if you have any questions regarding this matter.