A broader interpretation of "substance or composition" - good news for patentees at the EPO?


A recent decision from the EPO Boards of Appeal (T 1252/20) potentially paves the way for more diverse products to be patentable in Europe using the medical use claim format.

The background:

Article 53(c) of the European Patent Convention (EPC) excludes methods for treatment of the human or animal body by surgery or therapy and diagnostic methods practised on the human or animal body from patentability. However, this does not apply to products, in particular substances or compositions, for use in any of these methods.

Furthermore, Articles 54(4) and (5) EPC provide that a claim to a known substance or composition for (specific) use in a method referred to in Article 53(c) EPC is novel, provided that the claimed use is not comprised in the state of the art. The definition of “substance or composition” referred to in Articles 54(4) and (5) EPC has been debated in European case law over many years, and is at the heart of the decision in T 1252/20.

Forty years ago, G 5/83 established the principles for patentability of medical use inventions, and emphasised that the application of the special approach to novelty is strictly limited to claims directed to substances or compositions intended for use in methods referred to in Article 53(c) EPC. T 2003/08 interpreted the conclusions of G 5/83 to mean that the substance or composition had to be responsible for the therapeutic effect, and further developed this to state that the substance or composition had to be the “active agent”. T 2003/08 also introduced the following criteria to be determined: “(a) the means by which the therapeutic effect is achieved and (b) whether that which achieves the therapeutic effect is a chemical entity or composition of chemical entities”. The criteria (a) and (b) of T 2003/08 were developed further in T 1758/15, and similar considerations were made in T 2136/15 and T 1345/18.

These decisions essentially restricted which materials could be defined as a “substance or composition” based on the mode of action, with the underlying materials being considered to have a physical mode of action and thus to act as a device once inside the body.

Interestingly and significantly, the decision in T 1252/20 considers the same questions around the interpretation of “substance or composition”, but arrives at a different conclusion to preceding case law.

Details of the case:

In the patent application underlying T 1252/20, claim 1 was directed to:

“A composition for use in reducing or eliminating cancerous cells in a subject by forming at least a partial blockage, lodging, occlusion or embolism in a blood vessel to deprive a tumour in the subject of blood supply, or in the treatment of patent ductus arteriosus (PDA) or major aortopulmonary collateral artery (MAPCA) in a subject, the composition comprising: a solution comprising an amphiphilic peptide in an effective amount and in an effective concentration to form a hydrogel under physiological conditions to allow at least a partial blockage of the biological vessel to effect embolization or cell necrosis therein…”

The application was initially refused by the Examining Division (ED) for lack of novelty, because the ED considered that the claim did not relate to a “substance or composition” and therefore the medical use claim format did not apply. Specifically, the ED said that the mode of action was purely physical and based on the macroscopic 3D-structure, and so the composition acted as a device in the human body and could not be considered a substance or composition in the sense of Articles 54(4) and (5) EPC.

However, the Board of Appeal disagreed with this view and was “convinced that the peptide solutions defined in the claim do qualify as “substance or composition” in the sense of Article 54(5) EPC, and that thus the claimed subject-matter is novel”.

The Board considered that the independent claim of the underlying patent application defined a material in a liquid state and did not define the material by any technical features which would be characteristic of a device, such as its shape. In the Board’s wording: “It is a shapeless liquid mixture of chemical entities and, already for this reason alone, it is not a device”.

In a departure from the approach of the prior case law, the Board concluded that “[t]here is no legal basis for the mode of action as a criterion for qualifying a material or object as a substance or composition under Article 54(5) EPC”.


The implication of T 1252/20 could be that the EPO will now allow medical use claims for any material or object that can be defined as a substance or composition, regardless of whether its mode of action is achieved by chemical means or physical means. This approach would be welcomed by patentees seeking to protect products which would have been categorised as a device when using the approach of the established case law.

However, it is currently unclear whether the EPO will in future adopt the approach of T 1252/20 when considering the patentability of medical use claims, or whether it will continue to adopt the approach as in the established case law. As such, care should be taken when drafting medical use claims for products until the EPO’s preferred approach becomes more clear.