Double Patenting at the EPO - Enlarged Board Referral

T 318/14

Currently, there exists conflicting case law on the issue of double patenting at the EPO. The Board of Appeal in T 318/14 seeks to gain some clarity on double patenting issues by referring certain questions to the Enlarged Board of Appeal.

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There are two ways via which double patenting at the EPO typically arises: (1) the granting of divisional applications claiming the same subject-matter as the parent, and (2) the granting of internal priority applications claiming the same subject-matter as the priority-claiming patent.

In G1/05, the Enlarged Board proposed the exclusion of double patenting in cases where the applicant "had no legitimate interest in proceedings that gave rise to the grant of a second patent in respect of the same subject-matter for which he already held a patent".

Nevertheless, in the case of option (2) above, there does exist a "legitimate interest", in that a patent granted on the priority-claiming application would have up to a year of extra term compared with that of a patent granted on the priority application itself.

T 318/14

After highlighting conflicting case law on the issue of double patenting in the case of internal priority, the following questions were referred to the Enlarged Board in T 318/14:-

1. Can a European patent application be refused under Article 97(2) EPC if it claims the same subject-matter as a European patent granted to the same applicant which 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 where 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 latter case, does an applicant have a legitimate interest in the grant of 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?


At first sight, it would appear that the Grounds for referral are valid. If the referral is deemed admissible by the Enlarged Board, it will be interesting to gain some clarity as to under which circumstances double patenting should represent a barrier against the grant of a patent. In particular, further clarification as to what constitutes a "legitimate interest" is most welcome.

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