b) New therapeutic application based on the group of subjects to be treated 

According to the established case law of the boards of appeal, the use of the same compound in the treatment of the same disease for a particular group of subjects, can nevertheless constitute a novel therapeutic application, provided that it is carried out on a new group of subjects which is distinguished from the former by its physiological or pathological status (see T 19/86, OJ 1989, 24; T 893/90, T 233/96, T 1399/04, T 734/12).

In T 19/86 (OJ 1989, 25) the board had to decide whether the application of a known medicament for the prophylactic treatment of the same disease in an immunologically different population of animals of the same species could be considered a new therapeutic application from which novelty for the claims could be derived. According to decision T 19/86 the question of whether a new therapeutic use was in accordance with decision G 5/83 should not be answered exclusively on the basis of the ailment to be cured but also on the basis of the subject (in the case in question, the new group of pigs) to be treated. A therapeutic application was incomplete if the subject to be treated was not identified; only a disclosure of both the disease and the subject to be treated represented a complete technical teaching. The proposal according to the application to protect animals which could not hitherto be protected from the disease in question, by intranasally administering to them a known serum, could not be considered disclosed in the prior art and therefore constituted a novel therapeutic application in accordance with G 5/83.

In T 233/96 the board held that if the use of a compound was known in the treatment or diagnosis of a disease of a particular group of subjects, the treatment or diagnosis of the same disease with the same compound could nevertheless represent a novel therapeutic or diagnostic application, provided that it was carried out on a new group of subjects which was distinguished from the former by its physiological or pathological status (T 19/86, OJ 1989, 25; T 893/90). This did not apply, however if the group chosen overlapped with the group previously treated, or the choice of the novel group was arbitrary which meant that no functional relationship existed between the particular physiological or pathological status of this group of subjects (here humans who were unable to exercise adequately) and the therapeutic or pharmacological effect achieved.

In T 694/16 the board held that if a claim is directed to a known compound or composition for use in a therapeutic method of treatment or prevention of a disease, and the claim specifies that the subject to be treated displays a clearly defined and detectable marker, which is not displayed by all subjects affected by or likely to develop that disease, then the purposive selection of the patients displaying the marker for the specified treatment is a functional feature characterising the claim. When reading the claim in a technically sensible and constructive manner, the skilled person would promptly understand that the purpose of the treatment is to target selectively prodromal patients identified by the CSF markers, rather than other subjects that do not display the markers. This implies that there is a functional relationship between the markers that characterise the patients and the therapeutic effect which is sought. The presence of this functional relationship confirms that the purposive selection of patients is an essential technical feature qualifying the claim. This has to be taken into account when assessing novelty.

In T 1991/17 a compound for use in the treatment or prevention of bone metabolic diseases associated with osteopenia by inducing osteogenesis was claimed. The respondent had relied on two aspects that would constitute a new specific use of a known compound in a method of treatment: 1) the term "by inducing osteogenesis" as a technical effect and 2) the sub-group of patients to be treated, distinguished on the basis of this technical effect. The term "by inducing osteogenesis" did not form part of the definition of the disease, but qualified the treatment of the disease. The question arose of whether it was to be considered a mere mechanistic explanation of the treatment, or whether this feature linked the treatment to a physiological effect suitable for establishing novelty. The board considered that the patent in suit provided information on a new mechanism of action of peptide D, one of the claimed compounds. This mechanism of action was closely and inseparably linked to the known activity of peptide D of inhibiting bone resorption. No evidence of complete uncoupling of these two activities had been shown. The claimed use could not be distinguished from the known use of peptide D. The technical effect of inducing osteogenesis was therefore not apt to constitute a new specific use.

In T 2232/17 the board did not see any evidence that patients suffering from MS and who are "dependent on steroids" differed in their physiological or pathological status from the general group of MS patients, in particular with respect to their suitability for being treated with natalizumab. The patent contained no data on the treatment of MS patients with steroids and/or natalizumab. Moreover, even if the patent were taken as disclosing a sub-group of "steroid dependent" patients, no special therapeutic or pharmacological effect of natalizumab in this sub-group was disclosed in the patent.