Enlarged Board of Appeal Decision on Double Patenting in Europe Leaves Important Questions Unanswered

We reported in March 2020 that questions concerning double patenting were being considered by the Enlarged Board of Appeal in case G4/19. The Enlarged Board of Appeal has now issued its decision, which can be found here. The EPO has also provided a helpful summary of the decision here.

The legal background behind the referral, and the specific questions referred, are discussed in our earlier news item. In brief, an examining division had rejected a European patent application on the basis that it claimed "100% identical" subject matter to its already-granted European priority application. The applicant was apparently pursuing this filing strategy because the European patent application would have an extra year of patent term as compared to its priority application. On appeal, the applicant argued that this additional year of patent term provided the applicant with a "legitimate interest" in being granted multiple patents for the same subject-matter.

Interestingly, there is no statutory prohibition on double patenting under the EPC. The legal basis for rejecting applications on the basis of double patenting is essentially judge-made, and has often been subject to significant criticism.

The questions posed to the Enlarged Board of Appeal have now been answered as follows:

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.

In answering question 1, the Enlarged Board of Appeal has confirmed that the EPO can rely upon Article 125 EPC as the basis to refuse applications for unallowable double patenting, despite there being no such explicit statutory prohibition. Rather, Article 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 recognised in the Contracting States.

Having reviewed the preparatory work, or "travaux préparatoires", from the 1970s when the EPC was drawn up, the Enlarged Board of Appeal concluded that a prohibition on double patenting was generally recognised in the member states at that time and that the position does not seem to have changed since. As such, the prohibition on double patenting constitutes a principle of procedural law within the meaning of Article 125 EPC.

The answers to question 2.1 mean that the prohibition on double patenting extends not only to applications filed on the same date, but also to parent and divisional applications, and to applications claiming the same priority. It seems that the Enlarged Board of Appeal considers the phrase "claiming the same priority" to cover the fact pattern at issue in referred decision, which was an EP case claiming priority from another EP case (as well as a different scenario in which two European patent applications claim the same priority date) [see paragraphs 9 and 10 of the decision on "Interpretation of the referred questions].

In view of the answer to question 2.1 c) and the underlying reasoning, the Enlarged Board of Appeal felt it did not need to provide a separate answer to question 2.2. In other words, there is no need to consider whether the applicant has a legitimate interest, such as an additional year of patent term, in obtaining two patents for the same subject-matter. The bar is thus absolute and does not have any exceptions.

While the Enlarged Board of Appeal has confirmed that double-patenting exists as a concept under the EPC, and has provided further clarity in relation to one aspect of this area of law, it is disappointing that the Enlarged Board of Appeal did not take the opportunity to address other aspects. For example, the Enlarged Board of Appeal did not address what "the same subject matter" means or consider the question of what "the same applicant" means. These two issues are likely to lead to much argument in the future.

With regard to the former point, it is unclear how different a claim must be to no longer be directed to "the same invention". Will a claim that differs merely by virtue of the wording relating to one feature be considered as directed to the "same invention"? With regard to the latter point, it has been a feature of patent law that two different applicants who each file a patent application on the same day for the same invention can each proceed to obtain a patent as if the other application did not exist. Accordingly, can the double patenting prohibitions as outlined by the Enlarged Board of Appeal be avoided by assigning one of the cases to a different applicant prior to grant?

Given that certain aspects of the law around double patenting remain unclear, it is possible that there will be further referrals to the Enlarged Board of Appeal in the future.