In recent opposition proceedings at the EPO, the European patent EP2771468 granted to The Broad Institute, Inc, et al. and directed to the highly valued and today much discussed CRISPR (gene editing) technology was revoked due to a subsequent PCT application, according to the Opposition Division, incorrectly claiming priority from a number of US provisional applications (see EP register). The patent proprietor has already filed a notice of appeal against the decision of the Opposition Division.
The reasoned decision is not yet available but in its preliminary opinion issued before the oral proceedings in the present opposition proceedings the Opposition Division discusses the requirements for validly claiming priority from an earlier application, and in particular the meaning of the term “applicant” under the EPC (Art 87(1) EPC) as opposed to under US patent law.
In the US, any one of a plurality of applicants for an earlier application can file a subsequent application for an invention disclosed in the earlier application. The various applicants can act independently and can each transfer their right to the application and/or their right to claim priority to another party, even with retroactive effect. This was the case for the European patent in question, which at the end of the priority year was filed as a PCT application that claimed priority from a number of US provisional applications with a plurality of applicants, not all of whom were listed as applicants for the PCT application.
Under the EPC, on the other hand, joint applicants are seen as a single legal unity and can only act together. For a priority claim to be valid, all of the applicants for an earlier application must be listed as applicants for the subsequent application. They may still transfer their right to the earlier application and/or the right to claim priority to another party but such transfer must take place before filing of the subsequent application in order for the priority claim to be valid.
For the opposed patent EP2771468, the consequence of some of the priority claims being deemed invalid was that the patent was revoked due to intervening prior art. The Opposition Division emphasizes that it would have been possible to correctly claim priority by concluding separate assignments between the applicants for the earlier US provisional applications regarding the rights to the European part of the PCT application but that such assignments would have had to be signed before the filing of the PCT application. Any evidence of the transfer can be presented later.
The outcome of this decision emphasizes the importance of ensuring that the applicant filing the subsequent application claiming priority is in in fact in possession of the right to claim priority. In this regard, it is not possible to retroactively transfer the right to claim priority after the filing date. The right to claim priority is a separate right from the right to the invention and is a matter of national law. In this regard, and further explaining the strict criteria for validly claiming priority, see also decisions from the EPO, T1201/14 and T577/11.