The boards have considered situations in which a new sub-group of patients has been identified for treatment with a known substance.
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 (see also T 893/90).
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 836/01 the board accepted that claims directed to the use of IL-6 to directly influence tumour growth and differentiation were novel over a prior art disclosure of the use of IL-6 to indirectly treat cancer by activating T cells, finding that a new technical effect resided in the medical indication of the treatment of cancer vs. enhancement of the immune system. Applying the principles of decision G 5/83 (OJ 1985, 64), the board concluded that the technical effect relied upon in the claimed invention identified a new clinical situation. Since a new clinical situation was inseparable, as an abstract concept, from a patient suffering under it, it had to be concluded that this new clinical situation also identified a new sub-group of subjects being treated (T 1642/06).