The Enlarged Board of Appeal of the European Patent Office (EPO) has issued its decision on the two consolidated cases G 1/22 and G 2/22.

The Enlarged Board of Appeal of the European Patent Office (EPO) has concluded that the EPO is competent to assess priority entitlement, and that there is a rebuttable presumption that an applicant claiming priority in accordance with the formal requirements under the EPC is entitled to do so. Our previous articles on this subject are here, and here.


Cases T 1513/17 and T 2719/19 concerned the questions of whether the EPO is competent to assess a party’s entitlement to claim priority, and whether the co-applicant of a PCT application who is different from the inventors named in the US priority application can in the European phase validly rely on the priority right under Article 87(1) EPC.

These questions were referred to the Enlarged Board after the Opposition Division and the Examining Division found the priority claim to be invalid because not all inventors who were named as applicants in a US patent application had assigned the priority right to the applicants of the respective European patent applications before the filing of the PCT application.


According to Article 87(1) EPC: “[a]ny person who has duly filed […] an application for a patent […] or his successor in title, shall enjoy, for the purpose of filing a European patent application in respect of the same invention, a right of priority during a period of twelve months from the date of filing of the first application”.

Key points

A distinction was made between the right to file a European patent application (i.e., the lawful title to the application and to the ensuing patent) and the right to claim the priority date for that application (i.e., the “right of priority” referred to in Article 87(1) EPC). Whilst the EPO is not competent to assess the applicant’s entitlement to the patent application, this provision was held not to apply to Article 87(1) EPC. Thus, the EPO was competent to assess an applicant’s entitlement to priority.

The Enlarged Board also found that the applicant’s entitlement to priority is presumed to exist if the formal requirements for claiming priority are fulfilled. Justification was provided as follows:

  1. all parties involved normally have an interest that an application benefits from a priority right,
  2. there are no formal requirements for the transfer of priority rights, and
  3. the applicant of the priority application has to provide support to the applicant claiming priority.

This presumption is rebuttable and applies in any case where the priority applicant is not identical to the subsequent applicant, regardless of whether the subsequent application is a PCT application.


At first sight, this decision is reassuring for applicants. A jointly-filed PCT application which designates a first party for one designated State and a second party for another designated State, and which claims priority from an earlier patent application filed by only one of the PCT applicants, implies an agreement between both parties, to provide a valid priority claim.

However, there are two points to watch out for. Firstly, the presumption of validity of the priority claim can still be challenged in opposition proceedings. Secondly, an exception to the presumption may arise if there are substantial factual indications to the contrary.

It is still best practice to obtain written assignments of any priority rights before filing a PCT application, to be able to demonstrate the validity of the priority claim, if challenged. This should help to avoid the situation where the patent is revoked, as per the CRISPR patent case.


Ashik Gandhi

Technical Assistant
Share this post