In T 609/02 the board pointed out that where a therapeutic application is claimed in the form allowed by the Enlarged Board of Appeal in G 5/83 (OJ 1985, 64), i.e. in the form of the use of a substance or composition for the manufacture of a medicament for a defined therapeutic application, attaining the claimed therapeutic effect is a functional technical feature of the claim (see G 2/88, OJ 1990, 93) and G 6/88, (OJ 1990 114) for non-medical applications). As a consequence, under Art. 83 EPC, unless this is already known to the skilled person at the priority date, the application must disclose the suitability of the product to be manufactured for the claimed therapeutic application.
If the description in a patent specification provides no more than a vague indication of a possible medical use for a chemical compound yet to be identified, more detailed evidence cannot be used later to remedy the fundamental insufficiency of disclosure of such subject-matter (T 609/02). Referring to T 609/02, the board in T 433/05 recalled that where a therapeutic application was claimed in the Swiss type form, attaining the claimed therapeutic effect was a functional technical feature of the claim. As a consequence, under Art. 83 EPC 1973 the application had to disclose the suitability of the product to be manufactured for the claimed therapeutic application (see also T 1685/10). Note, however, that according to G 2/08 (OJ 2010, 456), where the subject matter of a claim is rendered novel only by a new therapeutic use of a medicament, such claim may no longer have the format of a so-called Swiss-type claim as instituted by decision G 5/83 (OJ 1985, 64). Following T 609/02, the board in T 801/06 the board recalled that a claimed therapeutic effect may be proven by any kind of data as long as they clearly and unambiguously reflect the therapeutic effect. Thus, the fact per se that the experiments in the patent were not carried out with a "real" metastasis was not sufficient to deny sufficiency of disclosure.
According to T 609/02, showing a pharmaceutical effect in vitro may be sufficient if for the skilled person this observed effect directly and unambiguously reflects such a therapeutic application (T 241/95, OJ 2001, 103, see also T 158/96) or, as decision T 158/96 also put it, if there is a "clear and accepted established relationship" between the shown physiological activities and the disease. Once this evidence is available from the patent application, then post-published (so-called) expert evidence (if any) may be taken into account, but only to back-up the findings in the patent application in relation to the use of the ingredient as a pharmaceutical, and not to establish sufficiency of disclosure on their own. See also T 491/08 and T 1364/08. This has also been applied to decisions concerning second medical use claims (see, for example, T 699/06 and T 1396/06) and in T 604/04, to claims directed to first medical use claims and to pharmaceutical compositions.
A post-published document reporting that no proven effective vaccine against HSV was available did not prove the non-workability of the invented vaccine, since there might have been other reasons, e.g. regulatory reasons, for not producing vaccines according to the invention. Furthermore, for compliance with the requirements of Art. 83 EPC 1973, it was not necessary to undertake and disclose clinical trials (T 1023/02).
For the acceptance of sufficient disclosure of a therapeutic application, it is not always necessary for results of clinical trials to be provided at the relevant date, but the patent/patent application must provide some information showing that the claimed compound has a direct effect on a metabolic mechanism specifically involved in the disease. Once this evidence is available from the patent/patent application, post-published evidence may be taken into account to support the disclosure in the patent application (T 433/05).