G4/19: Double Patenting Decision Solves Only Half the Problem

G 4/19 confirms that a European patent application can be refused if it claims the same subject-matter as a European patent which has been granted to the same applicant, even where it does not form part of the state of the art. Whilst this appears to provide some certainty, there is no guidance on what constitutes the same subject-matter.

An outstanding issue in European patent law is the extent to which an applicant can obtain two patents for the same invention. This issue arises more often than one might expect because applicants often file divisional patent applications, or maintain first and later filed applications for the same invention.

The Enlarged Board of Appeal were responding to a referral in case T 0318/04 from the Technical Boards of Appeal which asked the questions:

• 1. Can a European patent application be refused under Article 97(2) EPC if it claims the same subject-matter as a European patent which was granted to the same applicant and does not form part of the state of the art pursuant to Article 54(2) and (3) EPC?
• 2.1 If the answer to the first question is yes, what are the conditions for such a refusal, and are different conditions to be applied depending on whether the European patent application under examination was filed
• a) on the same date as, or
• b) as a European divisional application (Article 76(1) EPC) in respect of, or
• c) claiming the priority (Article 88 EPC) in respect of a European patent application on the basis of which a European patent was granted to the same applicant?
• 2.2 In particular, in the last of these cases, does an applicant have a legitimate interest in the grant of a patent on the (subsequent) European patent application in view of the fact that the filing date and not the priority date is the relevant date for calculating the term of the European patent under Article 63(1) EPC?

In the case under appeal in T 0318/04, a first European patent was granted, and a second European patent application, claiming priority to the first European patent, and including identical claims, was refused. The appellant argued that there was insufficient legal basis to warrant such a refusal, particularly in the case where priority was claimed.

Double patenting is a term used to refer to the situation where the same subject-matter is protected by the same applicant in two different patents. Double patenting is often prohibited in many patent systems around the world as there is considered to be no legitimate reason for an applicant having two patents directed to identical subject-matter.

For example, under UK patent law, double patenting is expressly prohibited under Section 18(5) of the UK Patent Act, though this is limited to applications having the same priority date. In practice, the limitation to applications having the same priority date has no real effect, because all other applications directed to identical subject-matter as an earlier application (having an earlier priority date) can be excluded from patentability under the novelty requirements. The European Patent Convention provides no such statutory exclusion to double patenting.

Whilst this appears to bring European patent law explicitly in line with the situation in many other territories, an important aspect of the test for whether the later European patent application should be refused is whether it relates to the same subject-matter as the granted European patent.

In many countries, for the purposes of double patenting, two patent applications are considered to relate to the same subject-matter, only if (some of) the independent claims are identical. Even very small variations in the independent claims are typically considered to provide a sufficient difference for both patents to be allowed to co-exist. It remains to be seen whether the European Patent Office will also adopt this narrow approach.

This update was prepared by Chris Cottingham, European Patent Attorney, who would be happy to discuss any of the issues raised in further detail.