The co-applicants approach derives support from T 1933/12. This Boards of Appeal (3.2.08) decision reasoned that Article 87(1) EPC does not prevent an applicant for a first application (P1) sharing their right to priority with a co-applicant for a subsequent application (A1) claiming priority from P1 (r. 2.4). Article 87(1) EPC merely requires that all of the applicants of P1 are also applicants of A1 (or their successor in title). Thus, an applicant may be named on the subsequent application that was not an applicant (or a successor in title of the applicants) of the priority application. 

Notably, Derk Visser is not a supporter of the Board's reasoning in T 1933/12, describing their justification of the co-applicant approach as "poor" (The Annotated European Patent Convention, Article 87(1)). Mr Visser further argues that the co-applicant approach of T 1933/12 is inconsistent with the EPO's reasoning that all applicants (X and Y) of the priority application (or their successor(s) in title) are named on the subsequent application claiming priority (as in the CRISPR case). The latter is based on the understanding that X and Y are a legal unity that cannot be divided, whilst the co-applicant approach permits a change of the legal unity of X+Y into X+Y+Z. 

A recent opposition decision considered the applicability of the co-applicant approach to a more complex situation. In this case, the PCT application claiming priority specified different applicants for different designated states. One of the applicants for the PCT application was not named on the application from which priority was claimed. So was the "extra" applicant entitled to priority?

The case related to GSK’s European patent EP 1965823, which was opposed by Sanofi, Novo Nordisk, Generics Ltd and Eli Lilly. The patent relates to GLP-1 for use in a method of treating diabetes. All four opponents argued that the patent was not entitled to priority from the US provisionals P1 and P2. The opponents argued that GSK had failed to provide evidence that, on the filing date of the PCT, the right to claim priority had been transferred from the inventor-applicants of P1 and P2 (Mr O’Neill and Mr Bush) to Smithkline Beecham Corporation (SBC) (for more on assignment of priority rights, see IPKat: Assigned or not assigned). 

During oral proceedings, GSK relied on the “co-applicants approach”. The PCT application had been filed in the names of SBC and the inventor-applicants of P1 and P2. SBC was listed as the applicant for all designated states apart from the US. Messrs O’Neil and Bush were listed as the applicants of the PCT for the US designation only. 

The Opposition Division noted that in the case of different applicants for different designations of a PCT application, the applicants are still considered co-applicants (Article 118 EPC). Legal basis for this position was provided in the form of J2/04, which relates to the legal status of co-applicants in general. According to J2/04, two persons who file an application in common cannot acquire a procedural status different from a single applicant, because otherwise each of them could perform different and contradictory procedural acts (e.g. filing a divisional). 

The Opposition Division further noted that there was no PCT provision preventing the application of the “co-applicants approach" to the international phase of a PCT application. On the contrary the PCT refers to the existence of “one single and common international application” (Article 3 PCT).  The Opposition Division concluded that:

The GSK patent was revoked on grounds other than invalid priority. GSK has appealed the decision. In reply to the appeal, Eli Lilly has argued that it was incorrect for the EPO to apply the co-applicant to the patent. Lilly particularly cites T 205/14  and T 517/14 in which the Board (3.3.01) required, in a situation analogous to that in the case in EP 1965823 (GSK), evidence of a transfer of the right to priority to the additional applicant (Z) of the PCT application from the applicants (X+Y) of the priority applications. None-the-less, the position of the Opposition Division in EP 1965823 is broadly in line with a number of opposition division decisions, e.g. EP2940044, and the Guidelines for Examination. 

There is another pending appeal challenging the co-applicant approach. The case relates to one of AbbVie’s Humria patents  (T 1837/19). In this case, Abbott Laboratories was listed as the applicant for the PCT application for all designated states apart from the US. The applicant-inventors of the US provisional applications from which priority was claimed were listed as the applicants for the US designation. The opponent has argued in their Statement of Grounds of appeal that the EP application is just one of the bundle of applications making up the PCT application, and that the EP application is different from and therefore does not include the applicants of the US provisional.

Unlike the issue at stake in the CRISPR appeal, the case law supporting the co-applicant approach is flaky at best. However, it seems likely that we will soon receive clarity on the legality of the co-applicants approach from the Boards of Appeal. Will the Boards of Appeal follow the more lenient approach to priority represented by the co-applicant approach followed by the opposition division, or will we see a tightening up of the requirements?