The scope of protection of a claim directed to a standard compound screening test carried out on "animals" encompasses preclinical tests carried out with libraries of compounds on human beings. In order for such a claim to be allowable under Art. 53(a), the use of human beings as "test animals" should be clearly excluded from the scope of the claim, e.g. by means of a disclaimer.
In some infrequent cases, a claim may, in the light of the description, be interpreted as exclusively relating to a clinical trial of an experimental medicament carried out on human beings. Such trials are ethically acceptable, since they are performed under strictly controlled conditions and with informed consent of the patient concerned. Therefore, no objection under Art. 53(a) should be raised (see however G‑II, 18.104.22.168).