The efficacy and safety of degarelix: a 12-month, comparative, randomized, open-label, parallel-group phase III study in patients with prostate cancer.
OBJECTIVE
To evaluate the efficacy and safety of degarelix, a new gonadotrophin-releasing hormone (GnRH) antagonist (blocker), vs leuprolide for achieving and maintaining testosterone suppression in a 1-year phase III trial involving patients with prostate cancer.


METHODS
In all, 610 patients with adenocarcinoma of the prostate (any stage; median age 72 years; median testosterone 3.93 ng/mL, median prostate-specific antigen, PSA, level 19.0 ng/mL) were randomized and received study treatment. Androgen-deprivation therapy was indicated (neoadjuvant hormonal treatment was excluded) according to the investigator's assessment. Three dosing regimens were evaluated: a starting dose of 240 mg of degarelix subcutaneous (s.c.) for 1 month, followed by s.c. maintenance doses of 80 mg or 160 mg monthly, or intramuscular (i.m.) leuprolide doses of 7.5 mg monthly. Therapy was maintained for the 12-month study. Both the intent-to-treat (ITT) and per protocol populations were analysed.


RESULTS
The primary endpoint of the trial was suppression of testosterone to <or=0.5 ng/mL at all monthly measurements from day 28 to day 364, thus defining the treatment response. This was achieved by 97.2%, 98.3% and 96.4% of patients in the degarelix 240/80 mg, degarelix 240/160 mg and leuprolide groups, respectively (ITT population). At 3 days after starting treatment, testosterone levels were <or=0.5 ng/mL in 96.1% and 95.5% of patients in the degarelix 240/80 mg and 240/160 mg groups, respectively, and in none in the leuprolide group. The median PSA levels at 14 and 28 days were significantly lower in the degarelix groups than in the leuprolide group (P < 0.001). The hormonal side-effect profiles of the three treatment groups were similar to previously reported effects for androgen-deprivation therapy. The s.c. degarelix injection was associated with a higher rate of injection-site reactions than with the i.m. leuprolide injection (40% vs <1%; P < 0.001, respectively). There were additional differences between the degarelix and leuprolide groups for urinary tract infections (3% vs 9%. P < 0.01, respectively), arthralgia (4% vs 9%, P < 0.05, respectively) and chills (4% vs 0%, P < 0.01, respectively). There were no systemic allergic reactions.


CONCLUSIONS
Degarelix was not inferior to leuprolide at maintaining low testosterone levels over a 1-year treatment period. Degarelix induced testosterone and PSA suppression significantly faster than leuprolide; PSA suppression was also maintained throughout the study. Degarelix represents an effective therapy for inducing and maintaining androgen deprivation for up to 1 year in patients with prostate cancer, and has a different mechanism of action from traditional GnRH agonists. Its immediate onset of action achieves a more rapid suppression of testosterone and PSA than leuprolide. Furthermore, there is no need for antiandrogen supplements to prevent the possibility of clinical 'flare'.
Klotz
Laurence
L
Division of Urology, University of Toronto, Sunnybrook Health Sciences Centre, ON, Canada. Laurence.Klotz@sunnybrook.ca
Boccon-Gibod
Laurent
L
Shore
Neal D
ND
Andreou
Cal
C
Persson
Bo-Eric
BE
Cantor
Per
P
Jensen
Jens-Kristian
JK
Olesen
Tine Kold
TK
Schröder
Fritz H
FH
D000230:Adenocarcinoma / Q000188:drug therapy*; D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000009:adverse effects / Q000627:therapeutic use*; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors*; D006801:Humans; D016729:Leuprolide / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides / Q000009:adverse effects / Q000627:therapeutic use*; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000188:drug therapy*; D013739:Testosterone / Q000378:metabolism; D016896:Treatment Outcome
D018931:Antineoplastic Agents, Hormonal; D009842:Oligopeptides; C431566:acetyl-2-naphthylalanyl-3-chlorophenylalanyl-1-oxohexadecyl-seryl-4-aminophenylalanyl(hydroorotyl)-4-aminophenylalanyl(carbamoyl)-leucyl-ILys-prolyl-alaninamide; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D017430:Prostate-Specific Antigen; D016729:Leuprolide