Ninety-five patients with stage C (C1 + C2) or D (D1 + D2) prostatic carcinoma were treated with the long-acting formulation of D-TRP-6 LH-RH (Decapeptyl) for up to 39 months. Of 88 patients evaluable for response, about one-half showed an objective response. In most cases, subjective improvement with relief of bone pain and/or urinary symptoms was obtained. Five patients claimed a mild increase in bone pain and one patient a slight worsening of dysuria following the first injection. Median progression-free survival was 13.1 and 16.4 months in patients with stage D2 and D1, respectively. Median survival in stage D2 patients was 27.6 months. These results indicate that the depot formulation of D-TRP-6 LH-RH offers an effective therapeutic alternative for patients with advanced prostatic cancer.