c) New technical effect 

In decision T 290/86 (OJ 1992, 414) the board considered the claimed invention new. The grounds for its decision were as follows: "When a prior document and a claimed invention are both concerned with a similar treatment of the human body for the same therapeutic purpose, the claimed invention represents a further medical indication as compared to the prior document within the meaning of decision G 5/83 if it is based upon a different technical effect which is both new and inventive over the disclosure of the prior document". In this case the technical effect considered new was the removal of dental plaque, whereas the prior art only disclosed the depression of enamel solubility in organic acids (see also T 542/96 and T 509/04).

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).

In T 2251/14 the board referred to T 836/01 and stated that a second medical use of a known substance can only be considered novel if the new technical effect leads to a truly new industrial/commercial application arising from the healing of a different clinical situation. It held that in the case in hand, the new technical effect of "enhancing the balance of beneficial and deleterious bacteria in the gastrointestinal tract of an animal having or at risk for inflammatory bowel disease (IBD)" defined a new medical use, since the claimed new technical effect identified a new clinical situation, namely one where it was possible to target the gastrointestinal flora of an animal having or at risk for IBD.

In T 1955/09, the board needed to decide whether the use claimed represented a further and different therapeutic use from the disclosure in document (D1). It stated that the conclusion could not be drawn that the technical effect relied upon by the claimed invention, i.e. the antibiotic effect, was a mere explanation of how the compounds inhibited or neutralised toxins. Rather, this effect identified a new clinical situation, namely one in which it could be preferable to target the infection itself, not merely the toxins produced by the bacteria or fungi causing the infection. The board decided that this reasoning was based on the differentiation of a direct and indirect effect on claims relating to second or further medical uses of a known substance (see above T 836/01 and T 1642/06). In view of the foregoing, the board was satisfied that the subject-matter of claim 1 at issue fulfilled the requirements of Art. 54(1) and (3) EPC vis-à-vis the disclosure in document D1.

In T 1972/14, the claim in question was a Swiss-type claim directed to the preparation of a certain infant formula so as to continuously reduce the circulating level of IGF-1 in the first few months of the life of an infant and thereby reduce the risk of development of obesity later in life. Reducing the risk of developing obesity later in life represented the therapeutic effect to be achieved, while the continuous reduction of the circulating level of IGF-1 represented the mechanism underlying this effect. A Swiss-type claim can derive novelty from the claimed therapeutic effect, but not from the mechanism underlying it. The prior art used the same formulation and the board held that the effect was thereby disclosed since the prior art in question started from the premise that there was a link between reduced protein content and obesity later in life.