EPO Enlarged Board establishes new practice in transfers of priority rights

Managing IP is part of Legal Benchmarking Limited, 1-2 Paris Gardens, London, SE1 8ND

Copyright © Legal Benchmarking Limited and its affiliated companies 2026

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

EPO Enlarged Board establishes new practice in transfers of priority rights

Sponsored by

maiwald-logo-cropped.PNG
pexels-rodolfoclix-1036936.jpg

Michaela Weigel-Krusemarck of Maiwald considers the impact of the Enlarged Board of Appeal introducing a rebuttable presumption that a patent applicant is entitled to claim priority

The EPO’s Enlarged Board of Appeal has decided that the transfer of a priority right is to be assessed solely according to the European Patent Convention (EPC). The Enlarged Board of Appeal’s consolidated decision G 1/22 and G 2/22 on October 10 2023 means national law will no longer be considered, thus departing from the previous practice (for example, T 1201/14).

Background to the decision

Due to the former need in the US to file a patent application in the name of the inventors, the EPO often confronted the scenario that a European patent (EP) application derived from a Patent Cooperation Treaty (PCT) application claimed the priority of a US application, wherein the applicants of the priority application differed from the applicants of the subsequent application. Whether there was an effective transfer of rights from the applicants of the US priority application to the applicants of the subsequent PCT or EP application was then (usually) examined by the EPO under US law. However, this is no longer the case.

According to the decision G 1/22 and G 2/22, an implicit agreement – for example, an implied transfer – is sufficient for a valid transfer, as the EPC does not have any formal requirements for the transfer of a priority right.

The Enlarged Board of Appeal has established a rebuttable presumption that the applicant is entitled to claim priority. This shifts the burden of proof to the effect that the party contesting the right to priority must prove that this right is actually lacking. The intention of the Enlarged Board of Appeal is to ensure that the priority is challenged less frequently in opposition proceedings.

Introduction of an implied agreement approach

The Enlarged Board of Appeal explicitly leaves open the question of the so-called PCT joint applicants approach. Instead, the Enlarged Board of Appeal establishes the concept of an implied agreement; according to which, the mere fact of the joint filing of a subsequent PCT application is sufficient for the parties to apparently have entered into an implicit agreement to the effect that an additional subsequent applicant may invoke the priority right conferred by the filing of the priority application by another subsequent applicant or other subsequent applicants.

Such an agreement may only be implied if all the applicants of the priority application or their successors in title (‘all applicants’) are also applicants of the subsequent application. However, even if this is not the case, the rebuttable presumption in favour of the priority right of the subsequent applicants still applies.

In this context, it is interesting to look back at the decision T 844/18 (CRISPR) in 2020, in which the board of appeal denied the validity of the priority claim due to violation of the ‘all applicants’ requirement. Against the background of the new decision by the Enlarged Board of Appeal, it is questionable as to what extent the application of the rebuttable presumption would have led to a different result in the above case.

Application of the new concepts

It remains to be seen how the opposition divisions and boards of appeal will implement the new concepts introduced by the Enlarged Board of Appeal in G 1/22 and G 2/22; for example, standards for rebutting the presumption. However, Dr. Martin Huenges and Dr. Kerstin Wolff, respectively a partner and counsel at Maiwald, who are familiar with the consolidated appeal cases T 2360/19, T 2516/19, and T 2689/19 due to their involvement in other CRISPR cases, report that the decision will be based on the new concepts of the Enlarged Board of Appeal, and the presumption of priority entitlement could not be rebutted in these cases.

Meanwhile, the Federal Court of Justice has already adopted this new EPO case law; for example, in Sorafenib-Tosylat and Happy Bit (linked-to pages in German).

more from across site and SHARED ros bottom lb

More from across our site

Ranjna Mehta-Dutt, who moved to Chadha & Chadha after 25 years at Remfry & Sagar, says the firm plans to expand its life sciences practice through targeted recruitment and dedicated teams for bigger clients
The initial contempt of court claim targeted Stobbs and the firm’s client for allegedly interfering with the administration of justice
Acquisition of platform developed by Boehmert & Boehmert lawyer set to create a combined platform for patent drafting and prosecution in Europe
Partner Rob Jacob unveils plans to offer a beginning-to-end trademark service, how to make prosecution profitable, and why IP ‘buy-in’ from the CEO stands the firm in good stead
Sponsored by CAS
CAS provides practical pointers on how intellectual property and R&D teams can work in tandem to unlock tangible benefits and avoid wasted spend
Sponsored by CAS
CAS explores how AI is transforming intellectual property, from inventorship and copyright disputes to new demands on patent attorneys
Sponsored by That.Legal
Gillian Tan of That.Legal discusses a recent decision by the Intellectual Property Office of Singapore and what it reveals about the evidential burden in bad-faith trademark claims
Attorneys at Di Blasi, Parente & Associados share how the protection of trade secrets strengthens innovation by bringing together legal practice, regulatory developments, and established international references
Jin Ooi, who joins as a partner today, said he is excited to offer a ‘rounded’ IP service as the firm deepens its litigation expertise in the UK and Europe
As generics celebrate, practitioners believe innovator companies should brace for an ‘uphill battle’ when trying to prove induced infringement
Gift this article