Change of category of claims: A change of category of granted claims in opposition proceedings is not open to objection under Article 123 (3) EPC, if it does not result in extension of the protection conferred by the claims as a whole, when they are interpreted in accordance with Article 69 EPC and its Protocol. In this context, the national laws of the Contracting States relating to infringement should not be considered.
"5. (...) It is generally accepted as a princi-ple underlying the EPC that a patent which claims a physical entity per se, confers absolute protection upon such physical entity; that is, wherever it exists and whatever its context (and therefore for all uses of such physical entity, whether known or unknown). It follows that if it can be shown that such physical entity (e.g. acompound) is already in the state of the art (for exam-ple in the context of a particular activity), then a claim to the physical entity per se lacks novelty. It also fol-lows that a claim to a particular use of a compound is in effect a claim to the physical entity (the compound) on-ly when it is being used in the course of the particular physical activity (the use), this being an additional technical feature of the claim. Such a claim therefore confers less protection than a claim to the physical enti-ty per se. An amendment of a European patent during opposition proceedings simply by way of change of category from a claim to a physical entity per se (e.g. a compound or composition), so as to include a claim to a physical activity involving the use of such physical entity, therefore does not extend the protection con-ferred by the patent, and is admissible."
New use of a known compound: A claim to the use of a known compound for a particular purpose, which is based on a technical effect which is described in the patent, should be interpreted as including that technical effect as a functional technical feature, and is accordingly not open to objection under Article 54 (1) EPC provided that such technical feature has not previously been made available to the public.
"7.1 (...) In relation to a claim to a use of a known entity for a new purpose, the question initially arises: what are the technical features of the claim? If the claim includes as a technical feature a "new means of realisation" by which the new purpose is achieved, in the form of steps of a physical activity, which are not disclosed in the state of the art in association with the known entity, then the claim is clearly novel because of the presence of that technical feature. In relation to a claim to a use of a known entity for a new purpose, the initial question is again: what are the technical features of the claimed invention? If the new purpose is achieved by a "means of realisation" which is already within the state of the art in association with the known entity, and if the only technical features in the claim are the (known) entity in association with the (old) means of realisation, then the claim includes no novel tech-nical feature. In such a case, the only "novelty" in the claimed invention lies in the mind of the person carry-ing out the claimed invention, and is therefore subjective rather than objective, and not relevant to the considerations that are required when determining novelty under Article 54 (1) and (2) EPC.
7.2 It follows that in the Enlarged Board´s judgement, in relation to a claim to a new use of a known compound (the new purpose of such use being the only potentially novel feature), if on its proper construction the claim contains no technical feature which reflects such new use, and the wording of the claim which refers to such new use is merely mental in nature and does not define a technical feature, then the claim contains no novel technical feature and is invalid under Article 54 (1) and (2) EPC (because the only technical features in the claim are known)."