Abarelix Depot, a GnRH antagonist, v LHRH superagonists in prostate cancer: Differential effects on follicle-stimulating hormone

Purpose: A Phase II clinical study contrasted the endocrinologic and bioche mical efficacy of Abarelix Depot, a gonadotropin-releasing hormone (GnRH) a ntagonist, with luteinizing hormone releasing-hormone (LHRH) superagonists, with or without additional antiandrogens, in men with prostate cancer. Methods: This study was open-label and treated 242 men. Albarelix Depot 100 mg was administered by intramuscular injection to 209 men, and LHRH, with or without an antiandrogen, was administered to 33 men according to the for mulation used. Serum concentrations of follicle-stimulating hormone (FSH) a nd other hormones were measured at baseline and at specified time points fo r the first 85 days of the study. Median serum concentrations of FSH at bas eline were similar for the two treatment groups. Results: Men treated with LHRH superagonists, with or without an antiandrog en, had a surge in the serum concentration of FSH on day 2 before FSH conce ntrations started to decline. Men in the Abarelix Depot group had an immedi ate and sustained decrease in the serum concentration of PSH, Conclusion: Recent data suggest that FSH may be an independent growth facto r for prostate cancer. The Abarelix Depot-induced decreased in FSH may have a role in the treatment of men with endocrine-responsive disease or for th ose men whose disease has escaped from hormone sensitivity.