Endocrine therapy for prostatic carcinoma--the clinical trial to compare the efficacy of LH-RH analogue, ICI 118630 (Zoladex) with castration or estrogen]

A multicenter randomized clinical trial was carried out between May, 1986 and May, 1987 involving 82 patients with stage B-D prostatic carcinoma from 29 centers. The clinical efficacy, endocrine effect, safety and usefulness of the luteinizing hormone-releasing hormone (LH-RH) analogue and other endocrine manipulations in the treatment of prostatic carcinoma. Zoladex depot containing 3.6 mg of ICI 118,630, an LH-RH analogue, was administered every four weeks 3 times in total. Patients in the control group received either 300 mg of diethylstilbestrol diphosphate orally daily for 12 weeks or orchidectomy. An antitumor effect (CR + PR) was observed in 21 of the 33 patients (63.6%) in the Zoladex group and in 22 of the 33 (66.7%) in the control group, showing no significant difference between the two groups. There was no significant difference in overall subjective response either; 21 of the 24 (87.5%) in the Zoladex group and 24 of the 30 (80.0%) in the control group. In both groups, 100% endocrine effect was obtained as shown by achievement of castration in all patients. Adverse reactions were observed in 14 of the 39 (35.9%) patients treated with Zoladex as compared with 19 of the 34 (55.9%) control patients, resulting in no significant difference in the incidence between the two groups. These adverse reactions were not so severe as to require withdrawal from the study. In both groups, the treatment was assessed as slightly or more useful in 29 of the 33 (87.9%) patients. From these results, it is concluded that Zoladex, 3.6 mg depot, is a useful drug for treatment of prostatic cancer, having clinical efficacy and endocrine effects comparable to those of the conventional endocrine manipulations, being safe, and causing less physiological and psychological pain.