Update of monotherapy trials with the new anti-androgen, Casodex (ICI 176,334). International Casodex Investigators.

Casodex (ICI 176,334) is a non-steroidal anti-androgen, which has a half-life compatible with once-daily oral dosing. In an open, phase II study on 267 patients given Casodex, 50 mg/day, an overall objective response (i.e. partial regression) was seen in 55.5% of patients (146 of 263) with a further 15.6% (41 of 263) having stable disease. Two of three randomized, phase III studies conducted with Casodex, 50 mg/day, showed it to be inferior to castration (either medical or surgical) on time to treatment failure and time to progression. A subsequent overview analysis of survival from these three studies showed a statistically significant difference in favour of castration. Prostate specific antigen (PSA) at 3 months correlated well with clinical outcome in the phase III studies of Casodex, 50 mg/day; a greater fall in PSA at 3 months was observed with Casodex, 100 and 150 mg/day, in an open dose-ranging study. As no significant tolerability issues were reported, further investigation of Casodex at these higher doses is in progress. All studies in which Casodex has been investigated have shown it to be a well-tolerated anti-androgen with a good side-effect profile compared with those reported for other available non-steroidal anti-androgens.