COST-EFFECTIVENESS OF ZOLEDRONIC ACID FOR THE PREVENTION OF SKELETAL COMPLICATIONS IN PATIENTS WITH PROSTATE CANCER

Abstract

We estimated the cost-effectiveness of zoledronic acid vs placebo for decreasing skeletal complications in men with prostate cancer. We performed a cost-effectiveness analysis alongside a multinational clinical trial of zoledronic acid. Cost estimation was based on prospectively collected resource use data for 85.3% of enrolled patients. Cost-effectiveness ratios were based on within-trial data on clinical outcomes, quality of life and study medication cost. Patients receiving zoledronic acid experienced fewer hospital days during a mean followup of 9 months (average 5.6 vs 8.0 days; p = 0.1910). Mean direct costs excluding study medication were US dollars 5365 for patients receiving zoledronic acid and US dollars 5689 for patients receiving placebo, a difference of US dollars 324 (95% CI US dollars 1781 to US dollars 1146). The global average cost of zoledronic acid plus its administration during the trial was US dollars 5677 (US dollars 450 per dose). The nominal cost per skeletal complication avoided was US dollars 112300 (95% CI US dollars 6900 to US dollars 48700) and the cost per additional patient free of skeletal complications was US dollars 51400 (95% CI US dollars 26900 to US dollars 243700). Nominal within-trial cost per quality adjusted life-year was US dollars 159200, which varied widely in sensitivity analyses. The nominal base case estimate of the cost per quality adjusted life-year for zoledronic acid in the prevention of skeletal complications of prostate cancer is consistent with that of bisphosphonates in breast cancer. However, the cost-effectiveness ratios for bisphosphonates are higher than commonly cited thresholds for conferring cost-effectiveness.