New data, published September 1 in the Journal of Urology, shows that Firmagon® (degarelix) which is a gonadotropin-releasing hormone therapy (GnRH) given to men with advanced prostate cancer may be superior to leuprolide when used over three years. This new study (CS21A) was an open-label extension of the Phase III study (CS21) in which Firmagon® was shown to be non-inferior to leuprolide in reducing testosterone to castrate levels through one year of treatment. In a retrospective analysis of the data generated by CS21, risk of PSA failure was significantly lower in men receiving degarelix versus leuprolide up to 1 year. CS21A, an extension study showed in an analysis that men who remained on Firmagon®, PSA suppression and the risk of PSA failure remained consistent over the long term (42 months).
In addition, in an exploratory analysis of CS21A, showed that men who crossed over from leuprolide to Firmagon® after one year also had their risk of PSA failure significantly decreased. At a median follow up of 27.5 months the data showed that the risk of PSA failure had decreased.
Longer time to PSA failure is thought to be desirable as it may delay the need to initiate second-line therapy, or chemotherapy. Time to castration resistance is also an important predictor of CRPC survival.
“This extension study supports using Firmagon® as first line-line androgen deprivation therapy in men with advanced prostate cancer locally advanced prostate cancer,” said E. David Crawford, MD, Head, Section of Urologic Oncology and Professor of Urologic and Radiation Oncology, University of Colorado Denver, US. “The data from the Phase III open-label extension study showed that Firmagon® provided advanced prostate cancer patients with safe and effective testosterone and PSA control over the long term, reducing the risk of PSA failure.”
Not withstanding this data, it does not factor in the significant potential risk of very severe localized injection site responses that seem to be experienced by many men who have chosen to use Firmagon®, making it unusable by many. Additionally, it is always risky to assume that retrospective studies accurately reflect reality.
Joel T Nowak, M.A., M.S.W.