Efficacy and Safety of Degarelix in Taiwanese Patients with Prostate Cancer Requiring Androgen Deprivation Therapy: An Open-label, Multicenter Phase III Study

Background: Pivotal phase III data have shown the efficacy and safety of degarelix (240 mg starting dose/80 mg maintenance dose [240/80 mg]) in North American and European patients with prostate cancer (PCa). This open-label, multicenter, single-arm trial has evaluated the efficacy and safety of degarelix in Taiwanese patients with PCa.Methods: Eligible patients received degarelix 240/80 mg monthly for 6 months. The primary objective was the efficacy of degarelix in achieving and maintaining serum testosterone below castrate levels (≤0.5 ng/mL). Secondary objectives included changes in serum testosterone and PSA, and safety.Results: One hundred and ten patients were allocated to treatment. Over six months, degarelix maintained serum testosterone at castrate levels; from Days 28-168, the cumulative probability of sustained castrate level testosterone was 97.2% (95% CI: 91.6-99.1%), meeting the primary objective. Degarelix rapidly suppressed serum testosterone levels, with castrate levels achieved by Days 3 in 93.5% of patients. PSA decreased rapidly from baseline, with a median reduction of 92.4% by Day 28. Degarelix was well tolerated, with the most frequent adverse events (AEs) being mild to moderate injection site reactions (ISRs), occurring mostly with the initial dose of degarelix. There were no immediate-onset systemic hypersensitivity reactions observed.Conclusions: In Taiwanese patients with PCa, a monthly degarelix 240/80 mg/mL dose regimen rapidly decreased testosterone and PSA levels, and maintained testosterone at castrate levels (≤ 0.5 ng/ mL) over 6 months. The safety profile of degarelix was consistent with that expected for elderly men with PCa undergoing androgen deprivation therapy (ADT).