EPO: Proving plausibility before the EPO

Managing IP is part of Legal Benchmarking Limited, 4 Bouverie Street, London, EC4Y 8AX

Copyright © Legal Benchmarking Limited and its affiliated companies 2025

Accessibility | Terms of Use | Privacy Policy | Modern Slavery Statement

EPO: Proving plausibility before the EPO

A common dilemma for inventors and applicants before the European Patent Office is whether an invention is sufficiently mature for a patent application to be filed. Although a proof-of-concept is often established at the date of filing, an inventor does not always have the opportunity to investigate every aspect of their invention before a patent is filed.

Typically, the EPO has been more relaxed than the USPTO or SIPO regarding this issue, and if an applicant at the EPO encounters an objection that a particular aspect of a claimed invention is not sufficiently disclosed, such an objection can typically be overcome by providing experimental evidence to the EPO that the aspect in question actually works as proposed. Experimental evidence of this nature can be post-published, i.e. the patent application can be supported by experiments carried out after the filing date.

EPO case law requires in principle that a patent claim should be examined for compliance with the requirements of sufficient disclosure (Article 83 EPC) on the basis of the application documents as originally filed. In practice, however, this requirement has not been strictly applied, and patents and patent applications often survive objections of lack of sufficiency, especially if post-published data can be provided.

Some recent decisions of the EPO Boards of Appeal in the pharmaceutical field have developed the existing case law around how plausible the technical effect of an invention must be at the filing date of the patent application.

In decisions T 0488/16 (Dasatinib I) and T 0950/13 (Dasatinib II), the Board required that the technical problem underlying the invention was at least plausibly solved at the filing date. This required technical evidence if the effect is "neither self-evident nor predictable or based on a conclusive theoretical concept". Post-filed evidence and declarations by experts that the products did in fact work as envisaged were not sufficient, and the patents were deemed to lack inventive step.

Decision T 2500/12 (Alzheimer) concerned an immunogen for a pharmaceutical composition in the accepted second-medical use form (for use in the treatment, prevention or amelioration in an animal of Alzheimer's disease or other diseases characterised by amyloid deposits). The Board was not convinced that the suitability of the immunogen claimed for the particular treatment was shown in the application as filed, or in the prior art. The patent claim was found to be insufficiently disclosed.

If these decisions form part of a trend, obtaining valid patent claims on the more speculative aspects of an invention may prove to be more difficult before the EPO.

Edward J Farrington

Inspicos A/S

Kogle Allé 2

DK-2970 Hoersholm

Copenhagen, Denmark

Tel: +45 7070 2422

Fax: +45 7070 2423

info@inspicos.com

www.inspicos.com

more from across site and ros bottom lb

More from across our site

Chris Sleep, Abion’s new head of litigation and dispute management, will work in the firm’s London office
Sources at four firms explain how changes to USPTO fees provide opportunities to give clients strategic counselling
An intervention by Dyson into the UK’s patent box regime and a report unveiling the major SEP owners were among the big talking points this week
With the threshold for proving copyright infringement by AI tools clearer than ever, 2025 could answer some of the key questions
Partners at Latham & Watkins and Finnegan reveal how they helped explain their client’s technology to a jury
One of Managing IP’s most influential people in IP for 2024, Hurtado Rivas discusses mental health in the profession, the changing role of a trademark lawyer, and what keeps a Nestlé IP counsel busy
Transactions specialist Mathilda Davidson, who has joined from Gowling WLG, says the firm will help clients seeking venture capital investment
Sources in the US, UK, and Australia hope that pressing questions surrounding AI and patent eligibility will finally be answered this year
Two partners who joined Brown Rudnick last year explain how their new firm’s venture capital experience is helping them accomplish their goals
Michael Gaertner explains why Locke Lord’s merger with Troutman Pepper sparked the need to seek a new home and why Buchanan Ingersoll & Rooney ticked the right boxes
Gift this article