Gonadotropin-releasing hormone antagonist: A real advantage?

Degarelix is a gonadotropin-releasing hormone (GnRH) antagonist that is approved for the treatment of prostate cancer. GnRH antagonists bind directly to and block GnRH receptors, without causing the initial testosterone surge associated with GnRH agonists. A pivotal phase III study indicated that degarelix induced significantly faster reduction of testosterone and prostate-specific antigen level than GnRH agonist does. In addition, its 5-year extension trial suggested that patients could be safely switched from GnRH agonist to degarelix treatment with sustained efficacy, as measured by biochemical markers. Possible benefits of GnRH antagonists over agonists were suggested especially in patients with advanced prostate cancer with metastatic and symptomatic disease. Moreover, the recent reports including pooled data analyses on degarelix suggest improved disease control, quality of life, and lower urinary tract symptoms and decreased risk of cardiovascular diseases when compared with GnRH agonists. However, interpretation of these reports should be conducted cautiously because of the potential biases involved. This article critically reviews the results of the clinical trials and subsequent analyses and evaluates the points and counterpoints of the conclusions.