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

BACKGROUND

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.

METHODS

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.

RESULTS

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 ≤0.50 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.

CONCLUSIONS

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.