Joint applicants and the right to claim patent priority in the EU

Establishing valid priority claims can be challenging for co-applicants in Europe, as Stéphanie Landais-Patarin explains.

csth B as the applicant for other countries (notably Europe), but claiming the priority of a US patent application filed by A.

In the absence of an assignment of the priority right from A to B, the priority was not deemed to be validly claimed and the European patent (EP) was revoked based on documents published after the filing date of the priority US patent application.

Co-applicants and European patents

On appeal, the patent owner relied on the ‘co-applicant approach’ followed by the EPO, which states that in the case of an EP application filed by co-applicants, it is sufficient for at least one of the co-applicants to have filed the priority application for the subsequent EP application to benefit from the priority date as the filing date. The patent owner argued that this approach was valid because a PCT application should have the same effect as an EP application, and in the case of an EP application, different applicants in different member states are co-applicants.

For its decision, the Board of Appeal decided to follow an alternative approach, according to which the applicable law is the law of the jurisdiction in which protection is sought, i.e., the European Patent Convention (EPC), which does not impose any formality as regards the assignment of the right of priority. Thus, the filing of the PCT application would be the very evidence that the right of priority was ‘implicitly’ assigned to other countries, since A consented to B being an applicant for countries other than the US.

The following questions were put to the Enlarged Board of Appeal, therefore:

1. Does the EPC confer jurisdiction on the EPO to determine whether a party validly claims to be a successor in title under Article 87(1)(b) EPC?

It should be noted that this is not the first time that this question of jurisdiction has been raised, and that it is still to be decided.

1. If the answer to Question I is in the affirmative: Can a party B validly rely on the priority right claimed in a PCT application for the purpose of claiming priority rights under Article 87(1) EPC where:

1) a PCT application designates party A as the applicant for the US only and party B as the applicant for other designated states, including regional EP protection, and

2) the PCT application claims the priority of an earlier patent application which names party A as applicant and

3) the priority claimed in the PCT application complies with Article 4 of the Paris Convention?

Patent applicants facing these priority problems are eagerly awaiting the decision of the Enlarged Board of Appeal. In the meantime, the  ‘co-applicant approach’ practised in the context of PCT applications should a priori be favoured.

Please get in touch with one of our European patent attorneys for further guidance or support, or contact us below.

Stéphanie Landais-Patarin is a Patent Attorney at Novagraaf in Paris.