A Prospective, Multicenter, Open-label Trial of Zoledronic Acid in Patients with Hormone Refractory Prostate Cancer

PURPOSE The short-term safety and efficacy of zoledronic acid for the treatment of skeletal metastasis was evaluated in patients with hormone-refractory prostate cancer. PATIENTS AND METHODS A total of 19 hormone-refractory prostate cancer patients with bone metastases were enrolled. All patients received up to six infusions of zoledronic acid (4 mg, given intravenously over 15 minutes, every 3-4 weeks). Safety was assessed by monitoring adverse events and serum creatinine levels. Efficacy was assessed by monitoring skeletal-related events, brief pain inventory score, quality of life score, type of pain medication, and analgesic score. Mean age of patients was 67.3 years (46-86 years), mean time from diagnosis of bone metastases was 27.6 months (0-117 months), and mean time from diagnosis of hormone-refractory disease was 7.5 months (0-26 months). RESULTS There was no clinically significant change in serum creatinine levels. Eleven adverse events (musculoskeletal disorders and systemic disorders) in 8 patients were classed as having a possible relationship to study drug. Fifteen patients completed six courses of zoledronic acid infusion. There were no significant changes in the brief pain inventory composite scores, quality of life questionnaire scores or analgesic score. No new skeletal-related events developed during the treatment period. CONCLUSION Zoledronic acid administered in this study as a 15-minute infusion demonstrated an acceptable and well-known safety profile in patients with refractory prostate cancer with bone metastases. However, prospective placebo- controlled clinical trials are required to elucidate the efficacy of zoledronic acid.