Comparison of efficacy and safety of 1-and 3-month luteinizing hormone-releasing hormone agonist depots as initial therapies for prostate cancer

We compared the efficacy and safety of 1- and 3-month depots of the luteinizing hormone-releasing hormone (LH-RH) agonist goserelin acetate in prostate cancer patients. Patients were randomly assigned to the Direct Group that received the goserelin 3-month depot or the Switch Group that began with the 1-month depot for the first 3 months and then switched to the 3-month depot. All patients were co-administered the antiandrogen agent bicalutamide. Serum testosterone and prostate-specific antigen (PSA) levels and adverse events were recorded at weeks 4, 8, 12, and 24. Baseline testosterone levels in the Direct and Switch Groups were 4.98 and 5.07 ng/mL, respectively (P = 0.798). At each week, the levels in both groups were a parts per thousand currency sign0.50 ng/mL (castration level) with no significant differences between them. All of the patients in the Switch Group and 98.1 % in the Direct Group had achieved castration levels at week 12, and 100 % had achieved such levels at week 24. Baseline PSA levels in the Direct and Switch Groups were 52.37 and 46.72 ng/mL, respectively (P = 0.793). Levels in both groups dropped continuously, to about 1.0 ng/mL at week 24, with no significant differences between the groups at any time. Three patients in the Direct Group experienced adverse events that were attributed to the co-administered bicalutamide. There was no difference in the efficacy or safety between the 1- and 3-month depots of goserelin when given as initial prostate cancer treatment in combination with bicalutamide. Patients must be monitored for adverse events associated with bicalutamide.