PSA response to secondary androgen deprivation following failed treatment of metastatic prostate cancer with the antiandrogen casodex

Casodex™ (ZENECA Limited) is a new antiandrogen presently under investigation for the treatment of metastatic prostate cancer. This study was designed to analyze response and possible prognostic significance of prostate specific antigen (PSA) monitoring when secondary androgen deprivation is administered at disease progression after treatment with a once-daily dose of Casodex 50 mg. Of the 31 patients receiving Casodex, 28 progressed and were treated with either orchiectomy or a luteinizing hormone releasing hormone agonist. Of the 23 patients who had follow-up PSA determinations, 19 (83%) showed a subsequent PSA decline. Median survival following secondary therapy was 22 months in the 14 patients whose decline was 50% or greater; survival was 17 months in the 9 patients whose PSA either rose or declined by less than 50% (p = 0.1711). s small study, reduction in PSA with medical or surgical castration following initial monotherapy with Casodex, 50 mg suggests incomplete androgen blockade with this dose of Casodex. While a trend suggesting a predictive value to PSA decline following secondary androgen deprivation was demonstrated, the change was not statistically significant.