NNC 01-0687, a selective dopamine D1 receptor antagonist, in the treatment of schizophrenia
Studies in rodents and nonhuman primates indicate that selective antagonism of dopamine D~ receptors in schizophrenic patients may produce antipsychotic action, including effects on negative psychotic symptoms with a reduced potential for induction of extrapyramidal symptoms (EPS) (Gerlach et al. 1995). Most of the dopamine D 1 receptor antagonists currently being evaluated have affinity for 5-HT 2 receptors in addition to their D 1 receptor affinity. The benzazepine NNC 01-0687 is a potent D 1 receptor antagonist with very low affinity for 5-HT 2, D 2 and other neurotransmitter receptors (Andersen et al. 1992). We report the results of a phase II clinical trial with NNC 01-0687. The objectives of the study were to evaluate safety and tolerance of NNC 01-0687 in hospitalised male schizophrenic patients and to perform a preliminary evaluation of antipsychotic effects. The study was conducted as an open label, multicentre study with a treatment period of 35 days. Changes in psychotic symptoms were assessed by means of the Positive And Negative Syndrome Scale (PANSS) (Kay et al. 1988) and Clinical Global Impressions (CGI) (Guy 1976). The Extrapyramidal Symptom Rating Scale (ESRS) (Chouinard et al. 1980) and a modified UKU Side Effect Rating Scale (Lingjaerde et al. 1987) were