Double trouble: EBA finds legal justification for the prohibition of double patenting (G4/19)

The Enlarged Board of Appeal (EBA) has issued its decision in G4/19, the last referral pending from 2019. The referral related to the legal justification for the prohibition of double patenting. This prohibition prevents the grant of more than one European patent application having the same filing date and applicant, and directed to the same subject matter. In its decision, the EBA reinforced previous case law prohibiting double patenting and found legal justification for the prohibition in the intention of the legislators (as evidenced in the travaux preparatoires). The full EBA decision in G4/19 can be read here

Background: Double patenting and legitimate interest 

The issue of double patenting had previously been considered by the EBA in G 1/05 and G 1/06. These decisions established in obiter a prohibition of double patenting in view of the fact that an 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" (G 1/05, r. 13.4). 

However, this reasoning proved unsatisfactory justification for the refusal of all cases of double patenting. There are circumstances in which an applicant may be said to have legitimate interest in a second patent for the same subject matter. An applicant may, for example, claim priority from a European patent application for a second European patent application directed to the same subject matter, so called "internal priority". The applicant could be said to have a legitimate interest in grant of this second patent, given that the second patent would have a later expiry date than the first (patent term being 20 years from the filing date, not the priority date). 

The arguable disconnect between the EBA reasoning in G 1/05 and G 1/06 against double patenting and situations of internal priority, has led to conflicting decisions by the Boards of Appeal. The Board of Appeal in T 1423/07, for example, found that legal basis for preventing double patenting can not be found, and that an applicant may have a legitimate interest in pursuing the second application in cases of internal priority (IPKat) (although in this particular case the applicants for the first and second application were different). By contrast, the Board of Appeal found in T 307/03 that double patenting is prohibited in cases of internal priority (IPKat). 

The referral on double patenting (G4/19)

The unclear case law on double patenting eventually led to the G4/19 EBA referral from the Board of Appeal in T 318/14. The appealed decision was a rejection from the Examining Division of application EP2429542. The application was rejected on the grounds that the claims covered subject matter identical to the granted priority application (EP09159932).

Double trouble

The referral asked whether a European patent application could be refused (under Article 97(3) EPC) if the application claims the same subject matter as a granted European patent (owned by the same applicant) that does not form part of the state of the art (pursuant to Article 54(2) and (3) EPC). The referral further asked if different conditions should be applied to applications filed on the same date versus cases of internal priority. 

The appellant in the case did not request oral proceedings, and so the EBA decision was issued by written decision only. 

Can Article 125 EPC be used as legal basis for a prohibition of double patenting

Article 125 EPC has often been cited as legal basis for the prohibition on double patenting (including by the President of the EPO in his comments on G4/19).  Art. 125 provides that, in the absence of its own procedural provisions, the EPO will take account of the relevant provisions of contracting states. The EBA evaluated whether Art. 125 could serve as legal basis for the prohibition of double patenting should the relevant provisions exist in contracting states. 

The EBA first considered whether the issue of double patenting could be said to be a "procedural provision", as specified by Art. 125. An objection under double patenting requires substantive examination, as applications must be assessed for the extent that they relate to the same subject matter. Could the "procedural provision" specified in  Art. 125 thus be said to extend to activities of substantive examination?

The EBA was confident that Art. 125 did indeed extend to the less formally "procedural" activities of substantive examination. The EBA drew an analogy to refusals during examination under Article 123(2) and (3) EPC (added matter). Art. 123(2) and (3), the EBA reasoned, are "procedural provisions", in that they are contained in Chapter I of Part VII of the EPC, and Chapter I is entitled "common provisions governing procedure". However, the EBA noted, Article 123(2) is very frequently used as a grounds of rejection in substantive examination. As such, the EBA reasoned, the term 'procedural provisions': "may well extend to provision requiring substantive examination of the subject matter", and Art. 125 may thus provide legal basis for the regulation of double patenting. 

Implementation of Article 139 EPC is not evidence of a general prohibition of double patenting in contracting states

The next question before the EBA was whether there did in fact exist, as a general principle, the prohibition against double patenting in contracting states. Proponents for a prohibition of double patenting cite the implementation by contracting states of Article 139 EPC as evidence of this prohibition. Art. 139 provides that contracting states shall determine what happens in circumstances where there is both a European and national patent, i.e. where a national patent and a European patent validation for the same subject matter is sought in a particular state. In the UK, for example, the Comptroller may revoke a UK patent on his own initiative in cases where a European patent owned by the same applicant, for the same subject matter, is subsequently validated in the UK (Section 73(2), UKPA). 

The EBA noted, however, that information on the implementation of Art. 139, such as by the UK, does not provide direct evidence of a general prohibition of double patenting in cases of two European patents (as opposed to a European patent and a national patent). The EBA therefore found it necessary to search for legal justification for a prohibition of double patenting elsewhere than in Art. 139

Legal interpretation from the Travaux preparatoires

The travaux preparatoires may be consulted in situations in which the meaning of the EPC is itself unclear (which the EBA found to be the case on the matter of double patenting) (Article 32(b) of the Vienna Convention). In the minutes of a meeting of the Diplomatic Conference (Minutes of the 6th Meeting) on Art. 125, there is acknowledgement of a common understanding that double patenting should be prohibited: 
During discussion of this Article the Conference established that the European Patent Office may not grant more than one European patent to the same person for the same invention being the subject of applications filed on the same date.
The Conference also established that the European Patent Office is entitled to correct any slips which it may make
It seems that Norway was the only voice of dissent on double patenting during these negotiations. The Norway delegation observed that "it could not agree to this principle [on the prohibition of double patenting] in its present general form since under Scandinavian law it was possible in theory to grant two patents to an applicant for the same invention.” (i.e. if these patents are filed on the same day). 

However, for the EBA, there could "be little doubt" from the records of these discussions that there was a majority agreement on the prohibition on double patenting as a generally recognised principle of procedural law in the contracting States. The travaux preparatoires therefore provided evidence of a procedural provision on double patenting in the contracting states relevant to Article 125 EPC. The EBA rejected any concerns that the agreement was not unanimous, noting that the text of EPC were themselves established by majority vote. The EBA concluded:
The preparatory documents demonstrate with overwhelming certainty that there was a real and effective agreement that the European Patent Office should prohibit double patenting by taking into account principles of procedural law generally recognised in the Contracting States, i.e. by a direct application of Article 125 EPC. 

Using Art. 125 as legal basis, the EBA thus answered question 1 of the referral (is there a prohibition on double patenting?), in the affirmative. The EBA concluded that this general prohibition thus prohibited double patenting in cases of internal priority. 

Final thoughts

The G4/19 referral, dealing as it does with the more legalistic aspects of patent law, has perhaps received less attention than the more high profile referrals on subject-matter eligibility (G1/19 (Computer simulated inventions) and G3/19 (Pepper, IPKat). However, had the G4/19 decision gone the other way, and acknowledged opportunities for double patenting in cases of internal priority, the consequences would have been significant for European patent strategy. Particularly, it would have given value to the filing and maintenance of European priority applications. As it is, users of the EPO can consider it business as usual with respect to double patenting objections from Examiners. 

Notably, the EBA did not consider it necessary to assess the meaning of "same subject matter" in its decision on double patenting. The EPO's current interpretation of "same subject matter" for the purposes of double patenting is relatively narrow, at least as compared as other jurisdictions (Case Law of the Boards of Appeal, II.F.V). In Japan and South Korea, for example, double patenting provisions can prevent applicants seeking grant of claims having any overlap in scope with previously granted claims (e.g. including broader claims). Those disappointed with the EBA decision in G4/19 can at least find comfort in the fact that pursuing divisional applications seeking broader protection than an already granted narrow patent, appears to remain a legitimate strategy before the EPO. 
Double trouble: EBA finds legal justification for the prohibition of double patenting (G4/19) Double trouble: EBA finds legal justification for the prohibition of double patenting (G4/19) Reviewed by Rose Hughes on Monday, July 05, 2021 Rating: 5


  1. The decision looks at a glance as giving a practical and pragmatic solution to the problem of double patenting. It fails however to convince.

    The problem occurs mainly with an “internal” priority that is a first filing as EP application followed by a second EP filing claiming the priority of the earlier one.

    Claiming that the “Travaux préparatoires” express the will of the contracting states although they have not taken a formal decision on this point goes a trifle too far for my liking.

    That purely formal rules can also have an influence on the substance is not to be denied, but when it is about Art 125, it can only be about formal aspects.

    Who can decide that an applicant cannot have a legitimate interest in doing something? The mere fact that such a double fling occurs shows that an applicant has a legitimate interest.

    The problem of double protection should be dealt with at national level as it is for instance the case when a PCT contracting state is designed directly or via the EPO.

    1. The sentiment expressed in the Travaux was actually quite explicit, if you read G4/19. Additionally, one of the key points of G4/19 was that a "legitimate interest" is irrelevant.

  2. According to thw wording of A.125 "the European Patent Office shall take into account the principles of procedural law generally recognised in the Contracting States."
    Having decided that A.125 could be applied to cover double patenting, it reached the opinion that it "is unable to conclude that the prohibition on double patenting is a principle generally recognised in the Contracting States."
    That, in my view, should have been the end of the matter. Revisiting the Travaux cannot determine what the current position is in the contracting states, as required by A.125, it can only provide an historic perspective. The Travaux were not created by the current contracting states, only a sub-section of them.


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