Klotz L et al. (2008) The efficacy and safety of degarelix: a 12-month, comparative, randomized, open-label, parallel-group phase III study in patients with prostate cancer. BJU Int 102: 1531–1538

Klotz et al. have compared the efficacy and safety of degarelix, a new gonadotropin-releasing hormone (GnRH) antagonist, with leuprolide, a GnRH receptor agonist, in a phase III study of men with prostate cancer.

A total of 610 patients (median age 73 years) participated in the 12-month, active-controlled, open-label, randomized trial. Patients received either a monthly 7.5 mg dose of leuprolide (intramuscular injection, 201 men) or one of two degarelix regimens: subcutaneous injection of 240 mg in month 1, followed by a maintenance dose of either 80 mg or 160 mg every month for 11 months (207 and 202 patients, respectively).

Sustained reduction of testosterone levels from baseline (median 3.9 ng/ml) to 0.5 ng/ml or less was achieved by 96.4%, 97.2% and 98.3% of patients in the leuprolide, degarelix 240 + 80 mg and degarelix 240 + 160 mg groups, respectively. Both degarelix doses reduced testosterone and PSA levels more rapidly than leuprolide; a transient 65% surge in testosterone concentration was observed in the leuprolide group at day 3. Maintenance of testosterone suppression was comparable for both drugs, and all three regimens were well tolerated.

Klotz and colleagues conclude that degarelix is an effective androgen deprivation therapy that does not induce the initial testosterone flare associated with GnRH receptor agonists, eliminating the need for antiandrogen supplementation.