Posted on 31/10/2023

It should go without saying but….

EPO Enlarged Board of Appeal significantly changes formal requirements for making a valid priority claim.

The European Patent Office (EPO) will decide whether a party is entitled to claim priority under Article 87(1) EPC and a recent decision by the Enlarged Board of Appeal has changed the position in a very positive way for applicants/proprietors (which is naturally less positive for potential opponents).

Article 87 EPC has previously been used to invalidate a priority claim in a European patent application which has led, in some case, to the patent being revoked for lack of novelty for example.  This has occurred on some high-profile patents, including European Patent No. EP2771468 which is one of many patents directed to the ground-breaking CRISPR technology.

The decision on EP2771468 centred on the EPO’s ‘all applicants’ interpretation of Article 87(1) EPC, namely, to require there to be identity of applicant(s) – taking account of successor(s) in title – between the applicant for the earlier priority–establishing application and the applicant for the later, priority–claiming application.

In relation to the priority provision in EPC Article 87(1), the Board of Appeal in T844/18 stated:

“the instances of the EPO have without exception adopted a consistent interpretation of Article 87(1) EPC since the inception of the European patent system”,

and in relation to the EPO’s ‘all applicants’ approach:

“[t]he continuation of such long standing and rationally based practices can be considered as an aspect of legal certainty”.

EP2771468 was revoked in opposition for lack of novelty, once the priority claim was deemed invalid. The Patentees appealed and the appeal was dismissed, the Board of Appeal confirming the earlier decision of the Opposition Division and agreeing with the EPO’s long-standing practice in interpreting Paris Convention Art. 4A(1) and EPC Article 87(1):

For a valid claim to priority under the EPC, the later application has to be filed by the same applicant or the same applicants (meaning all of the applicants, omitting none) who filed the earlier application. Thus, for a first filing by multiple applicants but a subsequent application by only one or some of those applicants it has to be shown that the priority right held jointly by the multiple earlier applicants had been transferred to the sole applicant or the group of applicants.

The situation was complicated further when a European patent application stemmed from a PCT application as that then also required interpretation of Article 4A(1) of the Paris Convention and consistency between Article 4A(1) of the Paris Convention and Article 87(1) EPC.

In the recent decision[6], the EPO Enlarged Board of Appeal decided that:

  1. The European Patent Office is competent to assess whether a party is entitled to claim priority under Article 87(1) EPC.

    There is a rebuttable presumption under the autonomous law of the EPC that the applicant claiming priority in accordance with Article 88(1) EPC and the corresponding Implementing Regulations is entitled to claim priority.

  2. The rebuttable presumption also applies in situations where the European patent application derives from a PCT application and/or where the priority applicant(s) are not identical with the subsequent applicant(s).

    In a situation where a PCT application is jointly filed by parties A and B, (i) designating party A for one or more designated States and party B for one or more other designated States, and (ii) claiming priority from an earlier patent application designating party A as the applicant, the joint filing implies an agreement between parties A and B allowing party B to rely on the priority, unless there are substantial factual indications to the contrary.

In the first portion of the decision, the Enlarged Board of Appeal discusses the basis of the right to claim priority, and more importantly, who under the EPC, has the right to determine whether a party is entitled to claim priority.

The Enlarged Board of Appeal firstly agreed that ‘the wording of Article 87(1) EPC (without reference to national law) that the transfer of the right of priority has to have been concluded before the filing of the subsequent European patent application (T 1201/14, Reasons, point; T 577/11, Reasons, point 6.5, Catchword 3; T 1946/21, Reasons, point 2.3).

Further, the Enlarged Board of Appeal clarifies that ‘the requirement that the right of priority has to be transferred before the -filing of the subsequent application can be described as a requirement based on autonomous substantive law under the EPC.’

The Enlarged Board went on to confirm that the title to the invention and the right to claim priority are separate rights, and although some written transfer documents expressly deal with the two rights separately, they are often considered together.  Given the many possible legal mechanisms under which a right to claim priority could be justified or explained, the Enlarged Board decided that the European Patent Office is competent to decide under Art 87(1) EPC whether the right to claim priority exists and went further in [110] to state that:

Like the priority entitlement in general, the presumption of its existence and the rebuttal of this presumption is subject to the autonomous law of the EPC only. Consequently, there is no room for the application of national laws on legal presumptions and their rebuttal.

Importantly, the Enlarged Board then considered at [104] that ‘the formal requirements for claiming priority in accordance with Article 88(1) EPC can only be met by the subsequent applicant if the priority applicant provides the necessary support completely and in time. The fulfilment of these requirements can thus be seen as strong factual evidence of the priority applicant’s approval of the subsequent applicant’s entitlement to priority’.

The Enlarged Board concluded at 105 that:

The Enlarged Board comes to the conclusion that entitlement to priority should in principle be presumed to exist to the benefit of the subsequent applicant of the European patent application if the applicant claims priority in accordance with Article 88(1) EPC and the corresponding Implementing Regulations.

Moreover, the Board held at para 99 that:

If national laws establish low or no formal requirements for the transfer of priority rights, the autonomous law of the EPC should not establish higher formal requirements than those established under national laws that may be relevant in the context of a European application. To the contrary, the EPO should adapt itself to the lowest standards established under national laws and accept informal or tacit transfers of priority rights under almost any circumstances.

This will certainly be good news for patent applicants and patent attorneys alike because it means that the up-to-now very strict requirement for ensuring that the applicants named on the priority application were also all named on any subsequent application leading to a European Patent (or that a written assignment of the right to claim priority was executed before filing the subsequent application) has been relaxed in favour of a more balanced and practical rebuttable presumption of entitlement to claim priority.

Of course, it should be borne in mind that the presumption of entitlement to priority can still be rebutted (e.g. by a party who filed the priority application) and that national laws can be more stringent.  Indeed, the Enlarged Board of Appeal reflected that attacks on formal priority started to become routine in EPO oppositions from about 2010, and it was speculated that such objections became popular after practitioners became alerted through some decisions of the United Kingdom courts.

As such, it remains good practice to ensure that the priority applicant(s) is(/are) the same as the applicant for a subsequent application, or that a written assignment of the right to claim priority takes place before the filing of the subsequent application, and the assignment document is kept safe. For more information about this and for any other enquiries please contact one of our patent attorneys.

Wilson Gunn