G2/21: A landmark decision of the Enlarged Board of Appeal on “Plausibility”


To be or not to be plausible, that is no longer the question. On March 23, 2023, the Enlarged Board of Appeal of the European patent office (EPO) rendered its long awaited decision addressing the question as to whether relying on post-filing evidence should be accepted to support inventiveness of a claimed invention.

Many examination and opposition procedures, as well as Appeal cases, had been suspended since November 2021, while waiting for the Enlarged Board of Appeal to shed light on the controversial notion of “plausibility”.

In a 75 page long, yet fluid, decision, referring to no less than 20 amicus curiae briefs, 3 observations by third party, 67 decisions of the Boards of Appeal, a number of national decisions, doctrine and references (all listed), the Board arrives at a rather simple conclusion, which we cannot help but applaud.

The Enlarged Board of Appeal recognized the effort of the referring Board to distinguish three lines of case law with respect to the requirement of inventive step (Art. 56EPC):

  • “ab initio plausibility” : post-published evidence can be taken into account if there is some preliminary data or at least a technical reasoning in the application as filed to support a technical effect
  • “ab initio implausibility” : post-published evidence must always be taken into account if the technical effect is not implausible, and
  • “no plausibility” (the concept of plausibility is rejected).

However, when analyzing the case law in more detail, the Enlarged Board of Appeal, dismissed such abstractness and found that “the core issue rests with the question of what the skilled person, with the common general knowledge in mind, understands at the filing date from the application as originally filed as the technical teaching of the claimed invention”.

To put it in a nutshell, a patentee may rely upon post-filed evidence in support of a technical effect if the skilled person would derive such technical effect from the original patent application as filed, or would consider it as being “encompassed by the technical teaching and embodied by the same originally disclosed invention”.

The practice should not change : inventive step should be analyzed on a case-by-case basis, considering what the skilled person understood from the application as filed.

Much ado about nothing, then?

While the decision has the merit of closing the debate on the ill-defined notion of plausibility in connection with inventive step, it also brings interesting comments extending to the requirement of “sufficiency of disclosure” (Art. 83EPC), especially for claims to a medical use. In such cases when the therapeutic effect is actually a feature of the claim itself, sufficiency of disclosure will be denied if it would not be credible to the skilled person that the therapeutic effect is achieved. Providing post-published evidence to remedy the absence of the experimental data in the patent application as filed will not help.

The Enlarged Board of Appeal thus confirms what European patent practitioners in the pharmaceutical, chemical or life science areas have been struggling with for years. Filing a patent application without at least some supporting data or detailed scientific rationale will turn out most challenging.



Discover the profile

Find our lastest news

Leaders League rankings 2023

We are proud to inform you that Becker & Associés has been distinguished once again by Leaders League as one of the top leading French patent firms in the Chemistry-Biotech-Life Science areas.

28 March 2023

Learn more

The Unitary patent: revised calendar

For technical reasons, the Unified Patent Court (UPC) has decided to postpone the start of the “sunrise period” to March 1, 2023. During this period, owners of European patents and patent applications may opt out from the exclusive jurisdiction of the JUB (“opt-out”), before the agreement on the unified patent jurisdiction enters into force in June 1, […]

8 December 2022

Learn more


The Unitary Patent (UP) and the Unified Patent Court (UPC) should come into force soon. The exact date is not certain, but should be end 2022 or early 2023. The Unitary Patent (UP) is a unique IP title which will allow for a protection in several member states of the European Union, with common validation and maintenance […]

26 April 2022

Learn more


September 4, 2021

Béatrice Tézier Herman has passed away so quickly, our pain is immense. A long-standing partner of the firm, Beatrice’s commitment and wisdom had been at the heart of the development and unity of our team. Your messages tell us about how an excellent professional she was, but also about her smile, her elegance, her serenity.

13 September 2021

Learn more

A look back at 2020: Two major decisions in the European landscape of pharma patents

Year 2020 was an active year for the Court of Justice of the European Union (CJEU), the judiciary arm of the European Union (EU) that is supposed to avoid inconsistent interpretations of the EU law over the Member States. With two decisions rendered in April and July 2020, the CJEU made some progress in clarifying […]

8 January 2021

Learn more

Post-grant Opposition in FRANCE: a new tool is introduced

The PACTE law (law n ° 2019-486 of May 22, 2019) relating to the growth and transformation of companies provided for several changes to patent law, aimed at enhancing the attractiveness and value of French industrial property titles. After extending the term of the Utility Certificate to 10 years, and creating a provisional patent application, […]

28 April 2020

Learn more

Discover all our news
Atomes 10


    If you would like more information, please do not hesitate to contact us. Please fill in the online form.


    Cabinet Becker et Associés

    25 rue Louis Le Grand

    75002 Paris

    Métro : Opéra

    Parking : Opéra-Meyerbeer

    +33 (0)1 53 43 85 00


    Cabinet Becker et Associés

    32 cours Mirabeau

    13100 Aix-en-Provence

    Parking : Mignet

    Social media & sharing icons powered by UltimatelySocial