In Decision G 4/19, the Enlarged Board of Appeal (EBA), whose main task is to ensure the uniform application of the European Patent Convention (EPC), has found that a European patent application can be refused by reason of the prohibition on double patenting.

The principle excludes two patents being granted to the same applicant for the same invention. The examining division applied this principle and refused the applicant’s European patent application under Articles 97(2) and 125 of the EPC on the ground that the applicant already had a patent for the same invention.

The applicant appealed and the Technical Board of Appeal (TBA) referred three questions to the EBA, asking whether there is a legal basis for the prohibition in the EPC. In particular, the TBA queried whether Article 125 was suitable for that purpose. Article 125 provides: “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 EBA interpreted Article 125 EPC in line with the principles set out in Articles 31 and 32 of the Vienna Convention on the Law of Treaties. It also took the preparatory works of the EPC (travaux préparatoires) into account.

The EBA held that the term “procedural provisions” in Article 125 extends to provisions requiring substantive examination of the invention claimed. It said that the prohibition on double patenting constitutes a principle of procedural law within the meaning of Article 125 EPC and is generally recognised in Contracting States.

Further, the EBA held that the prohibition on double patenting is not limited to applications for the same invention filed on the same day. It also extends to parent and divisional applications, and to applications claiming the same priority. The EBA also confirmed that the prohibition only applies where the application under examination and the patent already granted have common designated Contracting States. To read the Decision in full, click here.