General Information

Firmagon (degarelix) is a Gonadotropin-releasing hormone (GnRH) receptor antagonist. It binds reversibly to the pituitary GnRH receptors, thereby reducing the release of gonadotropins and consequently testosterone.

Firmagon is specifically indicated for the treatment of advanced prostate cancer.

Firmagon is supplied as a powder to be reconstituted with sterile water for subcutaneous administration in the abdomen. The recommended initial dose of the drug is 240 mg given as two subcutaneous injections of 120 mg at a concentration of 40 mg/mL. The recommended maintenance dose of Firmagon is 80 mg given as one subcutaneous injection at a concentration of 20 mg/mL, every 28 days.

Mechanism of Action

Degarelix is a Gonadotropin-releasing hormone (GnRH) receptor antagonist. It binds reversibly to the pituitary GnRH receptors, thereby reducing the release of gonadotropins and consequently testosterone.

Side Effects

Adverse events associated with the use of Degarelix may include, but are not limited to, the following:

• hot flashes
• injection site reactions
• weight gain
• increase in liver enzymes
• tiredness
• hypertension
• back and joint pain
• chills
• urinary tract infection
• decreased sex drive and trouble with erectile function

Clinical Trial Results

FDA approval of Firmagon was based on the results of a clinical trial. This open-label, multi-center, randomized, parallel-group study enrolled 620 subjects with prostate cancer. The subjects received one of two degarelix dosing regimens or leuprolide for one year: Group A) Degarelix at a starting dose of 240 mg (40 mg/mL) followed by monthly doses of 160 mg (40 mg/mL) subcutaneously; Group B) Degarelix at a starting dose of 240 mg (40 mg/mL) followed by monthly doses of 80 mg (20 mg/mL) subcutaneously; or Group C) leuprolide 7.5 mg intramuscularly monthly. The primary objective was to demonstrate that Degarelix is effective with respect to achieving and maintaining testosterone suppression to castration levels (T < 50 ng/dL), during 12 months treatment. In Group A (240/160 mg) there were 199 responders and the castration rate was 98.3%; in Group B (240/80 mg) there were 202 responders and the castration rate was 97.2%; and in Group C (leuprolide 7.5 mg) there were 194 responders and the castration rate was 96.4%.