30 June 2021

EPO confirms prohibition on double patenting – but leaves questions outstanding

Last week the European Patent Office (EPO)’s Enlarged Board of Appeal gave its decision in case G 4/19, in which it had been asked to clarify whether or not double patenting is excluded under the European Patent Convention (EPC), and if so, how that exclusion should be interpreted. The Enlarged Board’s answer essentially confirms existing EPO practice, but stops short of providing the full extent of clarification that had been sought.

Background to the case

Some EPC states, including the UK, have provisions under their national law which aim to prevent double protection for the same invention by both a patent granted under national law and one granted by the EPO. However, the EPC does not contain any explicit provisions banning double protection of the same invention by two EPO-granted patents.

Despite this, the EPO’s practice in recent years has been to refuse to grant patents in circumstances where two applications belonging to the same applicant have identical claims, have the same filing or priority date, and designate overlapping groups of contracting states. In such situations the EPO requires the applicant to either choose one application to proceed to grant, or else to amend the claims of one or both applications, or amend the designated states to remove overlap. As legal basis for this practice the EPO has relied 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 the applicant already possesses one granted patent for that subject-matter”.

This practice has been highly controversial, not least as it originates from obiter dicta in two earlier Enlarged Board decisions which were concerned with the assessment of added matter in connection with divisional applications, and not with the issue of double patenting per se. The legal basis for these obiter dicta, and so for the EPO’s consequent practice, was uncertain. Questions had also arisen as to the interpretation of this exclusion: for example could an applicant be said to have a ‘legitimate interest’ in obtaining two patents for the same subject-matter based on the additional year of protection provided by one application claiming priority from an earlier application with the same claims?

In decision T 318/14 of 7 February 2019, Technical Board of Appeal 3.3.01 considered the issue of double patenting in detail. After reviewing the legislative background to the EPC and the provisions of the EPC itself, the Board came to the conclusion that it was questionable whether or not the EPC provided any legal basis for the EPO’s practice, and that it may be more appropriate to introduce a prohibition on double patenting through a revision to the EPC rather than through case law. In view of this uncertainty, the Board referred a detailed series of questions to the Enlarged Board of Appeal to seek to clarify whether a legal basis existed for the EPO’s practice excluding double patenting; and, if such a basis existed, what conditions could give rise to a double patenting objection.

The Enlarged Board’s decision

In its decision G 4/19, the Enlarged Board recognised that it was being asked to provide a comprehensive ruling on all of these outstanding questions. However, it opted to keep its decision very narrowly focused, and to consider only the issue of legal basis for a double patenting exclusion without exploring the wider implications of such an exclusion beyond the underlying facts of the case which had led to the referral.

The decision provides a lengthy – although, to this author, not entirely convincing – survey of the legislative history behind the EPC, coming to the conclusion that a prohibition on double patenting arises from the intent of the legislator as it may be derived from the travaux préparatoires to the EPC. In the Enlarged Board’s view, this prohibition arises if a patent “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”. The prohibition is applicable if a patent:

  • was filed on the same date as an already-granted patent of the same applicant claiming the same subject-matter; or
  • is a divisional application of an already-granted patent of the same applicant claiming the same subject-matter; or
  • is an ‘earlier application’ in the sense that it is a parent, grand-parent, etc. of the already-granted patent of the same applicant claiming the same subject-matter; or
  • claims the same priority as an already-granted patent of the same applicant claiming the same subject-matter.

This prohibition only applies to the extent that the two applications/patents designate overlapping groups of contracting states.

Questions left unanswered

Given the focus of the Enlarged Board’s decision on providing a legal basis for the EPO’s existing practice, important questions are left unanswered. In particular, the Enlarged Board essentially restricted itself to the facts of the underlying case, in which the same legal entity had acted as applicant in respect of two patent applications having identical claims, one of which claimed priority from the other. The Enlarged Board’s decision therefore provides a legal basis for the EPO to continue refusing patent applications in situations having similar facts, i.e. where the claims and the applicant are undoubtedly the same. However, the wording of the decision leaves open the possibility of disputes regarding the identification of ‘the same subject-matter’. For example, regardless of current EPO practice, does this also potentially apply to partially overlapping claims? The criteria for identification of “the same applicant” have also been left unaddressed. Current EPO practice is to interpret this narrowly, such that a prohibition on double-patenting can be circumvented by, for example, assigning one of the patents or applications to another company within the same corporate group. However, further challenges to the interpretation of these provisions cannot be ruled out.

The Enlarged Board’s stipulation that the prohibition applies only in respect of overlapping designated states also leaves questions unanswered as to how this might be enforced in practice. For example, if both patent applications are still pending, at what point does any overlap in respect of the designated states need to be removed, and how will the EPO monitor to ensure that this is complied with, e.g. if a decision to grant one application has been announced but not yet come into force?

The decision may therefore come as a disappointment in some respects, given that the Enlarged Board has passed up the opportunity to define clear tests and to set clear limitations on the scope of this prohibition. On the other hand, given the criticism which has been levelled at the Enlarged Board for the wide-ranging repercussions and heavily political nature of a number of its other recent decisions, the relative restraint of this decision may be welcome, in that it does not signify any immediate changes to the EPO’s existing practice.