Prostate cancer is commonly associated with lower urinary tract symptoms (LUTS). The use of GnRH agonists or antagonists (first line ADT) is widely used as the primary treatment for advanced prostate cancer (pc) and/or to reduce prostate volume (TPV). It is thought that the ADT contributes to the development of LUTS.

Researchers pooled multiple other research findings to compare efficacy of the GnRH antagonist degarelix (Firmagon) with the GnRH agonist goserelin (Zoladex) in improving LUTS in men at different stages of prostate cancer.

They pooled data from three phase 3, randomized clinical trials with men receiving once-monthly treatment for 12 weeks with either degarelix (n=289; 240/80 mg) or goserelin (n=174; 3.6 mg) + bicalutamide (50 mg) for initial flare protection. LUTS symptoms were evaluated at weeks 4, 8, 12 and compared to baseline.

Adjustments were made for potential confounders. Prostate cancer stages were categorized by TNM as localized: T1/2 and NX/0 and M0; advanced: T3/4 and (NX/0 and M0) or (N1 and M0) or M1. Adverse events were assessed throughout the trials.

They found significantly greater declines in LUTS in men taking degarelix, compared to goserelin at week 12 corresponding with a greater proportion of men on degarelix with clinically relevant LUTS relief.  The clinical benefit for the degarelix therapy was especially pronounced in men with moderate-to-severe LUTS and with advanced prostate cancer.  A two-fold likelihood for an early (week 4) clinically relevant LUTS relief was seen with degarelix compared to goserelin.

No difference in castration efficacy (testosterone and PSA), TPV or urinary tract infection-related adverse events (2%) was seen between the treatment groups.

In summary degarelix was associated with an early, significant and clinically more pronounced improvement of LUTS, especially in men with moderate-to-severe LUTS or advanced prostate cancer. This symptomatic benefit may be linked to the different mechanism of action.

Clinical trial information: NCT00833248.

J Clin Oncol 32, 2014 (suppl; abstr e16017^);  Malcolm David Mason, Zsolt Bosnyak, Anders Malmberg, Anders Neijber; Cardiff University, Cardiff, United Kingdom; Ferring Pharmaceuticals, Copenhagen, Denmark

Joel T. Noak, M.A., M.S.W.