In an appeal case (T318/14) the legal basis in the EPC for refusing an application for double patenting, and the conditions for any such refusal, were questioned. Board 3.3.01 referred the following questions to the Enlarged Board of Appeal:
"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?"
The appeal before the referring Board was against the Examining Division (ED) refusing a patent application under Art. 97(2) EPC in conjunction with Art. 125 EPC. The application at stake claimed subject-matter identical to that of an earlier, directly filed, European application from which it claimed priority (so called internal priority’). Granting a second patent on this claim was held contrary to the principle of the prohibition on double patenting. The ED found the applicability of the prohibition was confirmed by an obiter statement in the Enlarged Board of Appeal’s decisions G 1/05 and G 1/06. The ED held that this prohibition also extended to European applications claiming an internal priority.
The appellant argued in its appeal that the prohibition of double patenting in G1/05 and G1/06 relating to divisional applications did not apply here, where the case is centred around internal priority. With reference to T1423/07 the appellant argued that there exists a legitimate interest in the grant of a second patent for the same subject-matter claiming internal priority. In particular, because the filing date, and not the priority date, is used to calculate the 20-year term of a patent, a second patent for the same subject-matter as an application from which it claimed internal priority could provide an applicant up to a year of additional protection for their invention. The appellant set forward that Art. 125 EPC would not be proper basis for the inhibition since the issue was not substantive law, the preparatory documents of the Convention (points 665. and 666. of the Minutes of the Diplomatic Conference establishing the Convention), showed there was no agreement on this issue within the meaning of Art. 31(2)(a) of the Vienna Convention on the Law of Treaties (VCLT) of 23 May 1969. Art. 139 EPC in turn demonstrated that double patenting was an issue left to national legislation. During the oral proceedings the appellant requested as a main request the grant of a patent and as auxiliary request referral to the Enlarged Board.
The Board set out an extensive legal analysis and in summary found none of Articles 60(1), 63(1), 76(1) and 125 EPC suitable legal basis for the prohibition. The Board’s doubt with regard to the applicability of Art. 125 EPC was based on 1) the wording and scope of Art. 125 EPC cannot be construed as encompassing a prohibition of double patenting nor are Art. 31 and 32 VCLT unambiguous in that regard, and 2) an interpretation on the basis of common agreement was not possible in view of the lack of agreement among the Contracting states during the Diplomatic Conference.
The president of the EPO was invited to comment on the referral and third parties given the opportunity to file submissions. The President of the EPO submitted that the legal basis for the prohibition was Art. 125 EPC, the intent to prohibit double patenting would be clearly derived from the preparatory materials of the Convention and the principle could be inferred from national legislation implementing Art. 139(3) EPC. The President the Office’s practice of applying the prohibition was correct and supported by G1/05 and G1/06. In contrast, the majority of the amicus curiae submissions supported the view that there is no proper legal basis under the Convention for a prohibition of double patenting.
The appellant in the case did not request oral proceedings, consequently the EBA decision was issued by written decision only.
The EBA found each of the questions of the referral admissible.
Question 1 was answered in the affirmative:
Art. 125 EPC specifies that ‘’In the absence of procedural provisions in this Convention, the European Patent Office shall take into account the principles of procedural law generally recognized in the Contracting States.’’
The EBA concluded that, from a purely systematic point of view, Art 125 EPC may provide a legal basis for the regulation of double patenting – regardless whether this means permitting or prohibiting it. Since it has been concluded that Art. 125 EPC may serve as the legal basis for a prohibition on double patenting, the next question was whether such a principle of procedural law exists and is generally recognized in the Contracting States. The EBA came to the view that approving the double patenting prohibition on the basis of the obiter dictum in G 1/05 and G 1/06, wherein the EBA did not explain in what way the prohibition on double patenting should be derived from the principle of a legitimate interest, would not be appropriate for the purpose of the present referral. There was no statement by the EBA in G 1/05 and G 1/06 that it regarded a ‘’legitimate interest’’ for double patenting in the proceedings to be a generally recognized principle of procedural law, which might have allowed the inference that Art. 125 EPC should apply. Therefore the EBA was unable to conclude that the prohibition on double patenting is a principle that is generally recognized in Contracting States and resourced to other sources. The EBA thus consulted the preparatory work of the convention, from which it emerges that the (future) Contracting States mostly agreed during the Diplomatic Conference on the fact that the prohibition of double protection was a generally recognized principle of procedural law and as such falling under the scope of (then) future Article 125 EPC.
The EBA found that the application of Art. 125 EPC as basis for the prohibition of double patenting did not depend on the relative filing dates of two European patent applications, but instead deemed that i) two EP applications filed on the same day, ii) a divisional application and its parent, and iii) a later EP application claiming priority to an earlier EP application should all be treated the same. The EBA thus concluded that the prohibition applies to all three scenarios a) to c) on the basis of the preparatory work of the Convention.
It follows that Question 2.2 did not require a separate answer.
Thus the EBA concluded the following:
1. A European patent application can be refused under Articles 97(2) and 125 EPC if it claims the same subject matter as a European patent which has been 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 The application can be refused on that legal basis, irrespective of whether it a) was filed on the same date as, or b) is an earlier application or a divisional application (Article 76(1) EPC) in respect of, or c) claims the same priority (Article 88 EPC) as the European patent application leading to the European patent already granted.
2.2 In view of the answer to Question 2.1 a separate answer is not required.