Is double patenting permissible at the European Patent Office? (G4/19)

The Enlarged Board of Appeal (EBoA), the highest judicial authority under the European Patent Convention (EPC), issued its decision in case G4/19 (double patenting) on 22 June 2021, in which it held that a European patent application can be refused based on the prohibition on double patenting, i.e. if it claims the same subject-matter as a European patent which has been granted to the same applicant and does not form part of the state of the art pursuant to Article 54(2) and (3) EPC.

The principle of the prohibition on double patenting, in most patent systems, excludes two patents being granted to the same applicant for one invention. However, the EPC does not contain an explicit prohibition against this practice.

In an earlier decision, the Technical Board of Appeal referred three questions on the prohibition on double patenting to the Enlarged Board of Appeal (T 318/14, OJ EPO 2020, A104). The referring board questioned whether there was a legal basis for the prohibition in the EPC. In particular, the referring board considered it doubtful that Article 125 EPC was suitable for that purpose.

In decision G4/19, the EboA confirmed that Article 125 EPC compelled the EPO to refuse applications for double patenting, because it is a principle of procedural law that is generally recognized in the Contracting States as evidenced by the preparatory works of the European Patent Convention. Decision G4/19 further clarified that the prohibition of double patenting applies regardless of whether it concerns two applications filed on the same day, parent and divisional applications, or an application and its priority application. Especially the latter case is important, as previous appeal decisions stated that there would be no reason for a refusal because there was a legitimate interest of the applicant to obtain a second patent with a longer duration.

However, decision G4/19 does leave some questions open. Indeed, no guidance on what constitute the same subject-matter or the same applicant is given by the EboA in the decision.

Although in many countries two patent applications are considered to relate to the same subject-matter only if the independent claims are identical, it remains an open question whether the EPO will consider, for the purposes of double patenting, very small variations in the independent claims to provide a sufficient difference for both patents to be allowed to co-exist. Under current jurisprudence, claims that are partially overlapping are not objected-to.

If you are willing to understand all the subtleties and the possible strategies underlying this long-awaited decision in case G4/19, we would be pleased to assist you. Please contact us!