Efficacy of zoledronic acid in the treatment of bone metastases secondary to renal cell carcinoma

Objective: This subset analysis examined the therapeutic effect of zoledronic acid on patients with renal cell carcinoma (RCC) and bone metastases. Patients with RCC may develop bone metastases, and these lesions rarely respond to therapy for RCC. Until recently, no bisphosphonate had been shown to be effective in RCC patients with bone metastases. Methods: A randomized, phase III, placebo-controlled study of zoledronic acid was conducted in patients with bone metastases secondary to a variety of solid tumors, including 74 patients with RCC. Analysis of efficacy in the RCC subset at 9 months was previously described, and 21-month follow-up data have now matured. Results: In the 9-month analysis, compared with placebo, zoledronic acid (4 mg) significantly reduced the percentage of patients with at least 1 skeletal related event (SRE) (37% versus 74%, respectively; p = 0.015) and reduced the risk for developing an SRE by 61% (p = 0.008). Median time to first SRE was 72 days for the placebo group and was not reached for the 4 mg zoledronic acid group in the 9-month analysis (p 0.006). Zoledronic acid 4 mg also significantly extended median time to bone-lesion progression at 9 months (p = 0.014). The 21-month analysis demonstrated that zoledronic acid provided continued significant improvements over placebo for time to first SRE and bone-lesion progression (p = 0.007 and p = 0.014, respectively). Safety of zoledronic acid was comparable with placebo throughout the trial. Conclusion: Zoledronic acid is highly effective at meeting the unmet need for treatment of bone metastases in patients with RCC. (C) 2004 Elsevier B.V. All rights reserved.