Casodex is a non-steroidal antiandrogen which shows marked peripheral selectivity in animals. As an antiandrogen, it has been shown in a dose ranging and an open phase II study to have fewer side-effects than traditional non-steroidal antiandrogens and to be very well tolerated. In the open phase II study, the 50 mg dose was used in 127 evaluable patients who have been treated for up to 1 year. Overall response (i.e. partial response [PR]) was 50% with a further 33% showing stabilization of disease.