Double Trouble: EPO Confirms Ambiguous Prohibition on Double Patenting

July 7, 2021
By Denis Keseris and Luca Manfredi

The Enlarged Board of Appeal of the European Patent Office (the “EPO”) issued a landmark decision1 on June 22, 2021. It confirms that, despite the European Patent Convention containing no specific provision prohibiting double patenting, the EPO is permitted to refuse a European patent application based on double patenting. The EPO will now need to develop an internal body of jurisprudence further defining the scope of double patenting, which practitioners will have to stay actively apprised of.

Nestlé’s European patent application 10718590.2 (the Application) claims priority from European patent 2251021 (the Patent). Whereas the Patent claims “a composition” and “a composition for treating”, the Application claims “a composition for use”. Faced with the Examining Division’s refusal on double patenting grounds, Nestlé appealed, and the Technical Board of Appeal referred2 the following three questions to the Enlarged Board of Appeal, the body tasked with ensuring a uniform application of the European Patent Convention (EPC):

  • Can a European Patent Application be refused if it claims the same subject matter as a European patent that was granted to the same applicant and does not form part of the state of the art?
  • If the answer to the first question is yes, what are the conditions for such a refusal, and do the filing dates, prosecution history, or claimed priority matter?
  • 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?

This referral allowed the Enlarged Board of Appeal to tackle double patenting at the EPO head-on. The Board essentially decided that a broad prohibition on double patenting exists in the EPC under Article 1253, which sets out that “[i]n the absence of procedural provisions in [the EPC], the European Patent Office shall take into account the principles of procedural law generally recognised in the Contracting States”. In its decision, the Board also made clear that this implicit prohibition applies to applications regardless of their history or priority4, before declining to answer the third question.

More specifically, after analyzing the works that led to the final text of the EPC, the Board concluded that most Contracting States prohibited double patenting in their national patent laws and had not intended to allow it in the EPC.

The full impact of decision G 4/19 remains uncertain because the Enlarged Board of Appeal failed to provide clear guidance on how broadly double patenting should be defined. Instead, the Board characterized double patenting in general terms, saying that it related to “the same applicant” pursuing two European applications to grant, which applications designated at least one overlapping country and were directed to “the same subject matter5.

Two contentious issues will require further clarification by the Boards of Appeal at the EPO, namely who can be considered as the “same applicant” and what constitutes the “same subject matter”.

The EPO has a long-standing policy of granting two patents when two different applicants file for the same invention on the same day. Faced with a double-patenting objection, an applicant at the EPO may, for example, attempt to overcome the objection by assigning one of the applications to a separate entity under their control, such as a subsidiary. Interpreted strictly, the applicants would no longer be the same. Decision G 4/19 does not provide guidance as to whether such a practice would be permissible.

The decision further fails to delimit the concept of the “same subject matter”. This expression is interpreted differently in different jurisdictions around the world, leading to a variety of practices when it comes to double patenting.

The United Kingdom, for instance, forbids two patents for the “same invention” in section 18(5) of the Patents Act 1977. UK Courts have construed it to apply where two patents either claim the same explicit combination of features, or one patent claims additional features that are implicit in the other. This has led to a very narrow interpretation of the “same subject matter” in the UK. As such, claims need to be almost identical in the UK to fall foul of double patenting prohibitions. The EPO’s position seems to be broader than this, as evidenced by the Technical Board of Appeal’s assertion that claims directed to “a composition”, “a composition for treating” and “a composition for use” are identical6 and thus “the same subject matter”. 

On the other end of the spectrum, Canada’s double-patenting practice requires claims to be “patentably distinct”. For applicants, this means examining the inventive concept in the claims of each application and ensuring that they are non-obvious with respect to one another. The fact that the Enlarged Board confirmed that the practice of pursuing a narrower “parent” patent application first and a divisional application with a broader scope sometime later was still acceptable7 would seem to indicate that their interpretation of the “same subject matter” is narrower than the Canadian interpretation.

The EPO could very well have deferred to national patent offices and courts, which are experienced in applying existing national laws and jurisprudence on the issue. Having broached the subject, however, the EPO will now be drawn into the work of fleshing out the scope of the new double patenting prohibition it has established.

1G 4/19, June 22, 2021

2T 318/14, OJ EPO 2020, A104, Order.

3G 4/19, Reasons, para. 76.

4G 4/19, Reasons, para. 89.

5G 4/19, Reasons, para. 2, citing T 318/14, OJ EPO 2020, A104, Reasons, paras. 17-13

6T 318/14, OJ EPO 2020, A104, Reasons, para. 24

7G 4/19, Reasons, para. 2, citing T 318/14, OJ EPO 2020, A104, Reasons, para. 24.

Subscribe to our newsletter

You can unsubscribe at any time. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

This site is registered on as a development site.