Priority: A possible new referral to the Enlarged Board of Appeal?

Priority: A possible new referral to the Enlarged Board of Appeal?

Last week, we observed oral proceedings for consolidated appeals T1513/17 and T2719/19, because a fundamentally important priority entitlement question was at stake. Specifically:
Is priority valid for a Euro-PCT application if the priority-entitled applicant is applicant for the US only on the PCT application, and there has been no transfer of priority rights to the applicant for Europe?
The Board of Appeal believes this issue concerns a point of law of fundamental importance that is decisive to both appeals, and, at the hearing, the Board indicated it was very likely to refer questions to the Enlarged Board of Appeal to clarify the correct approach.


One of the requirements for a valid priority claim at the EPO is that the European application is filed by the applicant for the priority application or their successor in title.
For many years it has been the EPO’s practice to acknowledge that priority is valid where the applicant for the priority application (or their successor in title) is amongst the applicants for the European application, as set out in Guidelines for Examination:
“However, in the case of joint applicants filing the later European patent application, it is sufficient if one of the applicants is the applicant or successor in title to the applicant of the previous application. There is no need for a special transfer of the priority right to the other applicant(s), since the later European application has been filed jointly. The same applies to the case where the previous application itself was filed by joint applicants, provided that all these applicants, or their successor(s) in title, are amongst the joint applicants of the later European patent application”. (Guidelines for Examination, A-III, 6.1)
In other words, provided that the priority-entitled person/entity is named as an applicant, the inclusion of additional applicants for the European application does not invalidate the priority claim. This is referred to as the “joint applicants” approach.
But is it enough for a valid priority claim if, in the context of a European application derived from a PCT application, the priority-entitled applicant is an applicant for the US only, and another applicant, who does not hold a priority right, is the applicant for Europe? That is the question at issue in these appeals.
This situation arises sometimes for US-based inventions. For example, a US provisional application may be filed in the name of the inventor and a PCT application claiming priority to this provisional may be filed with the inventor listed as an applicant for the US-only. Another (usually corporate) applicant is then listed for all other designated states. If no transfer of priority rights has occurred, the applicant for the US-only (the inventor) is the only applicant holding a priority right.
On the face of it, it may seem that a transfer of priority rights would be needed from the inventor (the priority-entitled applicant) to the applicant for the European designation, in order for priority to be valid in Europe. In this regard, the Guidelines explicitly refer to the priority-entitled applicant as being “amongst the joint applicants of the later European patent application”.
But, on the other hand, the PCT applicants for different designated states could be considered as joint applicants, as the PCT application is a single application having unitary character. The applicants for the different states could be considered as all acting together (as they are in the case of joint applicants for a European application) – in which case perhaps no transfer of rights is needed in order for priority to be valid in Europe. This concept can be referred to as the “PCT joint applicants approach”.
In the last few years, a number of Opposition Division decisions have followed this PCT joint applicants approach; but there has yet to be a Board of Appeal decision endorsing this approach.

The cases in question and need for an Enlarged Board referral

T1513/17 is an appeal against the decision to revoke a European patent, while T2719/19 is an appeal against the decision to refuse a divisional patent application in the same family. In these cases, the negative first instance decisions were based on an alleged lack of priority entitlement (because the priority-entitled applicants are US-only applicants on the PCT application). As a result, novelty-destroying documents form part of the state of the art.
Prior to raising the PCT joint applicants argument the patentee/applicant (Alexion Pharmaceuticals, Inc.) had argued, unsuccessfully, during earlier proceedings that a correction to the applicant should be allowed in order to resolve the priority issue. This argument was not expanded on in the appeal oral proceedings and the Board indicated that they were not inclined to accept the request for correction. The patentee/applicant now argues that it is sufficient that the inventors (holding the priority right) are among the applicants for the PCT application, even if only for the US designation. The applicants for the US are said to introduce the priority right into the PCT application with full effect for the application as a whole.
During the appeal hearing, the patentee/applicant (and indeed one of the opponents) argued in favour of the PCT joint applicants approach. Arguments were also made as to whether the EPO is competent to decide on legal aspects of priority entitlement (something that was discussed in the infamous “CRISPR priority appeal”, T844/18) and whether a person with no substantiated ownership interest in the priority right could challenge the patentee’s entitlement.
Interestingly, the legal member of the Board also suggested a possible legal reasoning by which the PCT joint applicants approach could be considered valid. Specifically, that the filing of the PCT application may show there was agreement between the US-only applicant and the applicant for all other designated states, thus meaning the applicant for Europe would be entitled to exercise the priority right. The legal member did flag that this approach may require an analysis of what the relevant law is for assessing an agreement.
The Board did not take a decision at the end of the hearing, instead choosing to deliberate before issuing a written decision. However, they did indicate that it was very likely they would be referring questions to the Enlarged Board of Appeal. But, will they limit the questions to the specific situation at hand? Or will they also refer broader questions such as whether the EPO has competence to assess legal entitlement?
We wait with bated breath!
If you have questions about a priority claim or a more general query on priority at the EPO, please contact Claire Weston, Kristina Cornish, Jamie Atkins or your usual Kilburn & Strode advisor.

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