Effects of bicalutamide and leuprolide on prostate-specific antigen (PSA),acid phosphatase (ACP) and prostatic acid phosphatase (PAP) in men with benign prostatic hyperplasia (BPH)

The effects of the nonsteroidal antiandrogen bicalutamide (Casodex(TM)) and the luteinizing hormone releasing hormone agonist leuprolide depot (Procre n Depot(TM). Lupron Depot(TM)) on serum prostate-specific antigen (PSA), ac id phosphatase (ACP), and prostatic acid phosphatase (PAP) in patients with benign prostatic hyperplasia (BPH) were determined. Thirty patients with B PH were randomised to receive bicalutamide 50 mg orally once daily or a pla cebo for 24 weeks, followed by 24 weeks of follow-up (bicalutamide study). In another study 55 men were randomised between 3.75 mg leuprolide depot in tramuscularly at every 28 days for 24 weeks or placebo injections (leuproli de study). In both studies blood sampling was performed at baseline, at wee k 12 at week 24 and 24 weeks after the end of therapy. Androgen suppression with bicalutamide 50 mg; daily for 24 weeks resulted in a median of 56% re duction of PSA (P < 0.001 when compared to placebo). Acid phosphatase and P AP did not change. Leuprolide resulted in a median of 87% reduction of seru m PSA (P < 0.001) and a 39% reduction of PAP (P = 0.023), whereas ACP was u nchanged. Both bicalutamide and leuprolide induced a pronounced decline in serum PSA in BPH patients. The studies suggest a stronger androgen suppress ive effect of leuprolide than of bicalutamide, but this difference might la rgely be due to too low a dosage of bicalutamide. ACP and PAP were relative ly insensitive to androgen suppression. Our study suggests a different degr ee of androgen suppression on PSA originating from benign tissue versus can cer tissue, and that the direction of this discrepancy might be different f or various androgen suppressive regimens.