Double patenting: legal fact or fiction? (G4/19)


The Enlarged Board of Appeal (EBA) has this week released its decision regarding the issue of double patenting.

The concept of double patenting will be familiar to those working in the patent field. It occurs when two different patents in the same jurisdiction claim the same subject-matter. If a claim has identical scope to that of a previous granted claim, the European Patent Office (EPO) will usually issue an objection. Yet, the European Patent Convention (EPC) does not explicitly refer to double patenting, leading to confusion as to whether an application can actually be refused on the ground of double patenting.

The question of double patenting was therefore referred to the Enlarged Board of Appeal of the EPO (EBA), in order to determine whether, and under what provision, an application could be refused due to double patenting. The Enlarged Board found that an application could indeed be refused, as a result of Article 125 EPC. This provision states:

In the absence of procedural provisions in this Convention, the European Patent Office shall take into account the principles of procedural law generally recognised in the Contracting States.

The Enlarged Board held that double patenting was a principle a procedural law within the meaning of this provision, and thus Article 125 EPC provides the source for the prohibition on double patenting.

Furthermore, the EBA held that the above did not depend on the relative filing dates of the two applications. They considered that i) two applications filed on the same day, ii) a divisional application and its parent, and iii) a later application claiming priority to an earlier application should all be treated the same in this regard. This is particularly important with regards to situation iii). Patent term is calculated from the date of filing, rather than the date of priority, so a later application claiming priority will protect its claimed subject-matter for up to a year after the expiry of protection from the earlier application from which priority is claimed. As a result, it was thought that an applicant may have a legitimate interest in pursuing an identical claim in a later application, in order to gain a longer period of protection. The decision in G4/19 has dismissed this concept, and means applicants will need to more carefully consider which claims to pursue in such situations.