A new referral to the Enlarged Board of Appeal of the European Patent Office on double patenting has the potential to influence patent filing strategies in Europe. Kristina Cornish and Oliver Lam take a look at some of the legal and practical implications of the referral.

What is double patenting?

Double patenting arises where two patents are granted to the same applicant for the same subject-matter. Although there are no provisions in the European Patent Convention (EPC) that explicitly address the issue of double patenting, the issue is referred to in the EPO Guidelines for Examination:

“…prohibition on double patenting is based 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 he already possesses one granted patent for that subject-matter” (Guidelines for Examination, G-IV, 5.4)

While the Guidelines permit co-pending applications by the same applicant with different subject matter or overlapping subject-matter, co-pending applications by the same applicant relating to the same subject-matter which designate the same European state(s) are not permitted.

Double patenting can be established in one of three ways:

  • Two patent applications filed on the same day by the same applicant

  • Parent and divisional applications

  • An application and its priority application

The referral to the EBA in T0318/14

T0318/14 relates to an appeal of the Examination Division’s decision to refuse an application claiming identical subject-matter to its priority application. The applicant argued that there was a legitimate interest in obtaining grant of the (second) application since the resulting second patent would have a later date of expiry.

The following three questions were referred to the Enlarged Board of Appeal (EBA):

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

  1. on the same date as, or

  2. as a European divisional application (Article 76(1) EPC) in respect of, or

  3. 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?

Legal and practical implications of the referral

Specifically, the referral aims to clarify whether double patenting resulting from an application and its priority application is permitted where an applicant can benefit from an extra year of patent term (i.e. whether this constitutes a “legitimate interest”).

More generally, the referral aims to clarify whether an application can be refused in relation to any type of double patenting and, if so, what the conditions are for refusal with respect to each type.

Due to the specific nature of the questions referred to the EBA in relation to the EPO’s approach to double patenting, there is also a potential clarification on what constitutes “legitimate interest” and “same subject-matter”.

Current filing strategies include the use of divisional applications to maintain pending claims. The EBA’s decision may therefore have important implications on filing strategies where there are potential double patenting issues between parent and divisional claim sets.

Double patenting is not currently a ground for opposition or revocation. If there are any potential double patenting issues, one strategy is to obtain grant of the application(s) before the EBA decision issues (expected in 2020). An alternative option is to wait until the EBA’s decision issues before deciding the best strategy. For example, examination could be prolonged by filing one or more divisional applications to keep options open.