EPO hints at accepting the ‘PCT joint applicants’ approach for priority

The EPO’s Enlarged Board of Appeal has issued a communication hinting that it is likely to endorse the so-called PCT joint applicants approach to priority. This should come as a relief to those with pre-AIA US priority applications. It also suggests a slightly more permissive view on priority entitlement, which could be favourable for patentees and applicants in a wider range of situations.

BACKGROUND

In recent years, entitlement to priority has been a hot topic at the EPO. Although basic priority requirements in most territories arise from the Paris Convention, the EPO’s strict interpretation and application of these requirements can come as a surprise to those in other countries.

This issue was particularly brought into focus in 2020 when one of the EPO’s Boards of Appeal dismissed the Broad Institute’s appeal against the Opposition Division’s decision to revoke a key patent relating to the CRISPR-Cas genome editing technology. In that case, the EPO confirmed its long-held position that, for a subsequent application to validly claim priority from an earlier application, it is necessary for all the applicants (or their successors-in-title) of the priority application to be joint applicants on the subsequent application - the so-called ‘all applicants approach’.

Although invalid priority entitlement is not itself a ground for revocation of a European patent, the loss of an earlier effective date can result in additional disclosures becoming prior art. This was the case for the CRISP-Cas patent, in which two novelty-destroying journal articles were only prior art due to the invalidity of the priority entitlement.

The case leading to the referral of questions to the Enlarged Board of Appeal in G1/22 and G2/22 raises related priority issues. In particular, it concerns whether a PCT application filed in the name of one party may validly claim priority from an earlier US application filed in the name of the inventor without a formal transfer of rights from the inventor, if the inventor is named in the PCT as an applicant for the US only. This has become known as the ‘PCT joint applicants’ approach.

THE FACTS AND ARGUMENTS

The case in question stems from an appeal against the decision of the EPO’s Opposition Division to revoke Alexion Pharmaceuticals’ EP1755674 following oppositions by Novartis, Hoffman-La Roche and Chugai Pharmaceutical; and an appeal against the decision of the EPO’s Examining Division to refuse the divisional application published as EP3056218.

The key issue was that Alexion Pharmaceuticals took the common pre-AIA approach of filing a US provisional application in the name of the inventors but filed a subsequent PCT application in its own name without formally transferring the right to claim priority from all the inventors to itself. Alexion Pharmaceuticals argued that its claim to priority is valid because the inventors were also named as applicants on the PCT application, albeit for the US only. 

The Board of Appeal held that the allowability of the PCT joint applicants approach was a point of law of fundamental importance relevant to a number of cases pending before the EPO’s Opposition Divisions and Boards of Appeal. The Board also held that despite extensive jurisprudence from the Boards of Appeal that the EPO has jurisdiction to decide on entitlement to priority, this would be a convenient opportunity to have a final decision from the Enlarged Board of Appeal on the matter.

As a consequence, the Board of Appeal referred the following two questions to the Enlarged Board of Appeal:

1. Does the EPC confer jurisdiction on the EPO to determine whether a party validly claims to be a successor in title as referred to in Article 87(1)(b) EPC?
2. If yes to Q1, 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 in a case where:
3. 1. a PCT-application designates party A as applicant for the US only and party B as applicant for other designated States, including regional European patent protection and
   2. the PCT-application claims priority from an earlier patent application that designates party A as an applicant and
   3. the priority claimed in the PCT-application is in compliance with Article 4 of the Paris Convention.

JUDGMENT

The Enlarged Board of Appeal’s latest communication provides important insights into its current views and the likely outcome of the referral.

Concerning Question 1, the Enlarged Board has not yet expressed its own opinion but revealed that the opinions of the parties and among the numerous amicus curiae briefs are evenly split.

Concerning Question 2, the Enlarged Board has commented that it is inclined support the PCT joint applicants approach. Although the Enlarged Board expressed reservations on whether this approach could be justified based purely on the wording of the existing legislation, it indicated that the approach is appropriate if a formal or informal agreement between the parties “can be assumed to exist”. The Enlarged Board went on to say that “the fact that a PCT application was jointly filed (i.e., with the consent of all applicants) could serve as evidence for the existence of such an informal or implied agreement”. 

The proposed approach also has the potential to affect the priority position in a wider range of situations. For example, an argument for priority entitlement could be made on the basis that the conduct of the parties is evidence of an informal or implied agreement between them.

The Enlarged Board of Appeal is set to deliberate on these points at oral proceedings on 26 May 2023, and a final decision is expected towards the end of this year.

IMPLICATIONS

The Enlarged Board of Appeal’s communication seems to indicate that it is likely to accept historic US practices around priority by endorsing the PCT joint applicants approach. This should come as a relief to applicants with pre-AIA US priority applications.

Although the Enlarged Board has not expressed an opinion about whether the EPO even has jurisdiction to determine whether a party validly claims to be a successor in title, we suspect that the Enlarged Board will ultimately decide to formally endorse the PCT joint applicants approach regardless of its answer to the jurisdiction question.