Although the EPC does not specifically prohibit double patenting, that is the grant of two patents to the same applicant for the same invention, it is generally accepted that two patents cannot be granted to the same applicant for the same subject matter. However, what is meant by "the same subject matter" has in the past caused some confusion as it too is not defined by the EPC. A recent case before the Technical Board of Appeal (T 1780/12) has shed some light on its meaning.
Both EP1 and EP2 related to the use of antibodies to aminophospholipids for cancer treatment.
The claims of EP1 were "Swiss-type claims" which are a form of purpose-limited process claim usually set out in the form "Use of X for the manufacture of a medicament for the treatment of Y"
The divisional application was filed after EPC2000 came into effect. EPC2000 allows for compounds which are useful in a method of treatment by therapy to be drafted as purpose limited product claims. The claims of EP2 contained such claims in the form "X for use in the treatment of Y".
EP1 was granted before EP2 and this forced the EPO to consider whether it could grant EP2 due to the restriction on double patenting. The EPO refused EP2 on the grounds of double patenting which prompted an appeal from UTS. The appeal focused on whether the EPO had neglected to focus on the scope of the claims and had focused too intensely on the language of the claims.
The Technical Board of Appeal (TBA) overturned the decision of the EPO.
The TBA first considered what is meant by the term "subject matter" in the context of double patenting. The TBA held that the subject matter of a claim was determined by two aspects, the category of the claim and its features. Using this analysis, the TBA arrived at the conclusion that EP1 and EP2 related to the same invention. However, for EP1 and EP2 to claim the same subject matter, and therefore fall foul of the objection, it was held that it was not enough for EP1 and EP2 to relate to the same invention.
The TBA held that the questions of what is the "claimed subject matter" in the context of double patenting is to be determined by the scope of protection afforded by the claims. In agreement with another Board of Appeal in T 1391/07, the TBA held that double patenting could only arise where EP1 and EP2 related to notionally the same scope of protection. Double patenting does not arise if the scope of protection conferred by the claims of EP1 and EP2 overlap only partially.
The claims of EP1 were purpose-limited process claims and the claims of EP2 were purpose-limited product claims. It is well accepted that a claim to a process confers less protection than that of a product claim. The scope of the claims of EP1 and EP2 were therefore different and so could not be seen to confer notionally the same scope of protection.
Whether double patenting is an issue is not merely an assessment of the category of conflicting claims but rather their features and claim scope.
Practically, to avoid double patenting, it is not sufficient merely to consider the wording of the claims and to arrive at a conclusion about protection based upon that wording, but to interpret the wording to arrive at a sensible picture of the scope of protection that is being sought. This assessment ought to be carried out at the time of filing a divisional application since it may be difficult to significantly change the scope of the claims of a divisional application later.