EPO Board of Appeal Decision emphasises that priority entitlement for a medical use claim requires more than finding words and dosages
In recently issued Decision T0883/23 of EPO Appeal Board 3.3.07, the Board explained at length its decision to refuse priority entitlement for a European patent claim relating to treatment for a particular cancer. This was despite the claim wording being arguably clearly derivable from the earliest priority application (P1) with reference to a dose escalation/de-escalation study.
The Board took the opportunity to emphasise the additional importance of data to render credible therapeutic efficacy consistent with the essential features of the claimed treatment as relied on for inventive step – they saw need for this in the context of the ‘same invention’ requirement for priority entitlement specified in Enlarged Board Decision G 2/98.
The claim of concern was in the ‘for use format’ for coverage of a combination therapy covering a first line treatment by injection at 2-week intervals of an irinotecan salt in liposomal form together with 3 other active agents, all the active agents having specified dosages. Priority was refused on the basis that specific combination of 60 mg/m2 liposomal irinotecan and 60 mg/m2 oxaliplatin as specified in the main claim of note was only mentioned in P1 in the context of an outline for a human dose escalation study/de-escalation study without indication of any preference for such dosages. The results of the dose escalation/de-escalation study were only presented in the corresponding PCT Application. While these showed that the combination therapy according to the claim under consideration was tolerated, they additionally showed that the alternative use of liposomal irinotecan at 80 mg/m2 with oxaliplatin at lower dosage was not favourable. Moreover, such dosage selection consistent with achievement of tolerability was not evident from the claims of any priority filing.
The Board rejected the Patentee’s argument that P1 describes the same subject matter as defined in claim 1 of the main request and hence should benefit from the priority of P1. They pointed to the established jurisprudence of the boards of appeal holding that that attainment of a claimed therapeutic effect must be regarded as a functional technical feature of a claim in the format permitted by Article 54 (5) EPC and that tolerability of the defined treatment is a prerequisite for therapeutic efficacy. They thus held that “the same invention” requirement of G2/98 for entitlement to priority from a priority filing cannot be divorced from technical information in a subsequent application essential for sufficient disclosure of a claimed therapeutic use.
Fortunately for the Patentee, the same focus of the Board on data in relation to the prior art meant that the claims were held novel and inventive in relation to the technical problem of providing an effective and tolerable alternative therapy.
A copy of the decision is available here.
