Objectives: To determine the safety and efficacy of zoledronic acid (Zometa) combined with imatinib mesylate (Gleevec) in patients with bone pain due to androgen-independent prostate cancer.
Methods: Fifteen patients were treated with zoledronic acid 4 mg intravenously every 28 days and imatinib mesylate 400 mg/day. The pain response, defined as a 2-point reduction in the Present Pain Intensity Scale or normalization if the initial score was 1, was the primary endpoint. Secondary endpoints included palliative response, prostate-specific antigen response, measurable disease response, time to progression, impact on quality of life, decrease in markers of bone turnover, and tolerability of the drug combination.
Results: The study was stopped early because of a lack of activity. No palliative or clinical activity was detected for the combination, and no prostate-specific antigen responses were observed. The median time to progression was 4 weeks (95% confidence interval 3 to 5), and the median duration of treatment was 8 weeks (range 1.6 to 16.7). The median overall survival was 54 weeks (95% confidence interval 18 to 90). Therapy was associated with a reduction in urine N-telopeptides and a trend toward a reduction in serum osteocalcin, but no change occurred in bone-specific alkaline phosphatase.
Conclusions: In this patient population, imatinib mesylate and zoledronic acid produced no prostate-specific antigen responses and had no palliative or clinical activity.