EPO Confirms Prohibition On Double Patenting ' But Leaves Questions Outstanding

• Published date: 01 July 2021
• Subject Matter: Intellectual Property, Patent
• Law Firm: Mathys & Squire
• Author: Alexander Robinson

Last week the European Patent Office (EPO)'s Enlarged Board of Appeal gave its decision in case G 4/19, in which it had been asked to clarify whether or not double patenting is excluded under the European Patent Convention (EPC), and if so, how that exclusion should be interpreted. The Enlarged Board's answer essentially confirms existing EPO practice, but stops short of providing the full extent of clarification that had been sought.

Background to the case

Some EPC states, including the UK, have provisions under their national law which aim to prevent double protection for the same invention by both a patent granted under national law and one granted by the EPO. However, the EPC does not contain any explicit provisions banning double protection of the same invention by two EPO-granted patents.

Despite this, the EPO's practice in recent years has been to refuse to grant patents in circumstances where two applications belonging to the same applicant have identical claims, have the same filing or priority date, and designate overlapping groups of contracting states. In such situations the EPO requires the applicant to either choose one application to proceed to grant, or else to amend the claims of one or both applications, or amend the designated states to remove overlap. As legal basis for this practice the EPO has relied on the notion that "an applicant has no legitimate interest in proceedings leading to the grant of a second patent for the same subject-matter if the applicant already possesses one granted patent for that subject-matter".

This practice has been highly controversial, not least as it originates from obiter dicta in two earlier Enlarged Board decisions which were concerned with the assessment of added matter in connection with divisional applications, and not with the issue of double patenting per se. The legal basis for these obiter dicta, and so for the EPO's consequent practice, was uncertain. Questions had also arisen as to the interpretation of this exclusion: for example could an applicant be said to have a 'legitimate interest' in obtaining two patents for the same subject-matter based on the additional year of protection provided by one application claiming priority from an earlier application with the same claims?

In decision T 318/14 of 7 February 2019, Technical Board of Appeal 3.3.01 considered the issue of double patenting in detail. After reviewing the legislative background to the EPC and the provisions of the EPC itself...