Post-filed data at the EPO: quo vadis?

Share on social media

06 October 2021

In a recent Board of Appeal case (T 0116/18) the Board proposed to the Parties to refer the question whether post-filed data could be relied on to satisfy the requirement of plausibility of a technical effect, to the Enlarged Board of Appeal.

For an applicant it is often a challenge to choose the ideal time of filing a patent application as it is important to find the right balance between filing early, even with not yet fully supported claims, and filing late thereby taking the risk that new publications appear in the state of the art jeopardizing their invention.

Previously, the EPO has accepted post-filing supporting data during the examination and/or opposition procedure. Such data was used in the problem-solution-approach when inventive step is assessed by the EPO. As explained in the Guidelines, there are three stages in this approach: 1) identifying the closest prior art, 2) determining the objective technical problem to be solved, and 3) starting from the closest prior art, examining whether or not the claimed solution to the objective technical problem would be obvious for the skilled person in view of the state of the art in general. The EPO assesses the objective technical problem in view of experimental data provided in the patent application, and historically also allowed new data, such as post-published data.

In the EPO, however, there emerged divergent case law which is sometimes contradicting when it relates to the question whether post-filed data is admissible for examining inventive step. Over the years, also several related questions remained unanswered and the notion of “plausibility” was introduced, limiting the circumstances in which such data could be used. The questions which arose vary from whether the burden to show that it was plausible that a technical effect is achieved rests with the Patentee (T1329/04) or with the Opponent (T184/16), to the question whether it is at the filing date that it needs to be considered that such plausibility is recognisable (e.g. T488/16).

Returning to the case which triggered the referral of questions to the Enlarged Board of Appeal, EP2484209, the TBA (T 0116/18) had to decide on a case relating to a composition and method for controlling insect pests using a combination of two compounds, one being thiamethoxam and the other represented by a genus of compounds (Markush formula). In the application as filed, only data relating to two specific compounds of the genus showed, in combination with thiamethoxam, a synergistic effect. The Opponent argued that it was not plausible at the date of filing that a synergistic effect could be achieved over the whole scope of the claim. The Patentee filed its own post-published-data showing other combinations of compounds falling under the scope of the claims and showing a synergistic effect.   

As mentioned at the beginning, the below provisional questions were recorded in the minutes of the hearing and are under consideration with the Patentee and the Opponent:

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)?

Only when the written decision on this case T 0116/18 is issued, the final wording of the questions will become known.

Quo vadis post-published-data at the EPO? The proceedings in this case now continue in writing until all comments of the involved parties are crystallized in clear questions and it will likely still take a few years before a decision is taken. Moreover, there is the question of what will happen to those cases which are still pending or under opposition, where the issue of admissibility of post-filed-data may have an impact on the outcome of the proceedings. It remains to be seen whether those cases will be stayed until the EBA has given its decision.

In the meantime, we invite our clients to inform us when drafting their patent application of all possible technical effects (even not yet proven ones) their invention may have, to allow us to secure the invention in all jurisdictions, if they intend obtaining a broad international protection.

If you have any questions, we would be happy to help. Feel free to reach out via email on

Follow us on Instagram