CABINET CHAILLOT

T0197/22 - sufficiency of disclosure of a medical use claim

medical use claim, sufficiency of disclosure

The patent proprietor filed the appeal against the decision of the opposition division to revoke European patent 3 318 248 ("the patent").
Claim 1 of the main request defines a pharmaceutical composition comprising a pharmaceutically acceptable excipient and at least one mRNA molecule encoding a peptide or polypeptide for use in therapy.
In the statement of grounds of appeal the patent proprietor argued that sufficiency of disclosure of a claim directed to the so-called first medical use of a composition under Article 54(4) EPC is to be acknowledged if the patent credibly discloses a specific therapeutic utility of the composition and that it is not required to demonstrate utility over the whole scope for any therapy and any disease.
The Board agrees with the patent proprietor that in case of a claim for a composition for use under Article 54(4) EPC it is not generally required for compliance with Article 83 EPC that a patent discloses the therapeutic suitability of the defined compositions in treatment of a plurality of diseases.
However, as claim 1 of the main request defines a composition for use in therapy, the patent must provide the skilled person with sufficient instructions for applying the compositions within the scope of the claim in some form of therapy without undue burden. In line with the considerations in G 2/21 this requires that the patent must substantiate the therapeutic utility of the claimed composition if in the absence of experimental data it would not be credible to the skilled person that any therapeutic effect is achieved.
Claim 1 of the main request defines the composition to comprise mRNA encoding a functional protein or enzyme. The patent demonstrates with in vivo experiments in mice that mRNA encoding firefly luciferase (FFL) may be effectively transfected and expressed using a liposomal transfer vehicle as defined in claim 1 of the main request.
The expression of FFL luciferase serves no purpose in any therapy. According to the proprietor, examples 7 and 8 provided nevertheless with the use of FFL proof of concept that the defined transfer vehicles allowed for the effective transfer and expression of therapeutically useful proteins.
The Board observes that claim 1 of the main request defines the encoded protein merely as a functional protein or enzyme and leaves the nature of the intended therapy still to be determined. The patent provides the skilled person no instruction for the therapeutic use of the mRNA encoding FFL when encapsulated in a transfer vehicle as defined in claim 1 of the main request.
Even if the term "functional protein or enzyme" in claim 1 of the main request is understood as functionally restricted to a protein with a feasible therapeutic utility, the Board considers that the patent does not provide the skilled person with a sufficient disclosure to generally enable the therapeutic use of the claimed formulation comprising the mRNA encoding for an accordingly defined protein.
The patent proprietor argued that FFL represented an established reporter gene for demonstrating effective gene transfer and that the experimental evidence in the patent provided thereby the crucial proof of concept for the suitability of the defined formulations in gene transfer therapy. Following this proof of concept, the skilled person was according to the proprietor well able on the basis of the instructions in the patent and the common knowledge to optimize the lipid compositions and to adjust the administered dose to achieve the therapeutically required levels of the protein of interest.
According to the Board, the mere detection of an unquantified level of expression of FFL using a particular formulation for gene transfer does not credibly disclose the general suitability of such a transfer vehicle for use in gene therapy, because in view of documents D64 and A106 serious doubts prevail that such a formulation allows to generally achieve therapeutically effective levels of expression of the contained mRNA. The Board is therefore not convinced that the patent provides actual proof of concept regarding the suitability of the claimed formulations for use in therapy.
The patent refers to parameters which may be modified to optimize transfection efficiency, including the selection of the lipids and their molar ratios as well as the size of the liposomal formulations. The patent further discloses that the compositions may be administered and dosed in accordance with current medical practice.
However, the Board considers that without substantiation of the suitability of a formulation for therapy to start with, these suggestions for optimization and dosing remain proposals for a research project which do not overcome the doubts regarding the suitability of the claimed formulations for use in therapy.
Accordingly, the Board concludes that the main request does not comply with Article 83 EPC.
The appeal is dismissed

 

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