EPO Enlarged Board establishes new practice in transfers of priority rights

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 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

Via LA’s Qi wireless charging patent pool now covers more than 50% of all SEPs in the space
Vida Panganiban-Alindogan at SyCip Salazar Hernandez & Gatmaitan discusses IP valuation and why no IP practice area is more important than the other
The IP team at Morais Leitão discusses high-stakes litigation, strategic partnerships with clients, and bolstering cross-border expertise
Eszter Szakács discusses 5.30 am wake-ups, legal mind games, and eating Nutella in the middle of the night
Counsel explain how AI can create brand protection headaches, but also be used to fight fakes
An AI copyright update in the UK and IP protection efforts by Temu and WeChat were also among the top talking points this week
Mary Till says she has been helping clients navigate policy questions, including staffing concerns at the office
A seminal decision concerning second medical use patents and questions over confidentiality were among the top talking points this fortnight
Managing IP considers some of the key themes from the 2025 Annual Meeting and offers some tips for London 2026
A comparison of the 2024 and 2025 editions of the Managing IP EMEA Awards reveals the firms and companies that have been dominating Europe’s IP market year after year
Gift this article