Effects of intravenous Zoledronic acid and oral ibandronate on early changes in markers of bone turnover in patients with bone metastases from NSCLC

Background The aim of this study was to assess the early effects of zoledronic acid (ZOL) and oral ibandronate (IBA) on the bone resorption marker s-CTX (serum C-telopeptide of collagen type I) and the bone formation marker B-ALP (bone-alkaline phosphatase) in patients with bone metastases from non-small cell lung cancer (NSCLC). Methods; Fifty-five patients with at least one site of bone metastasis secondary to NSCLC were randomly assigned to receive intravenous ZOL 4 mg every 4 weeks, or oral IBA 50 mg/day. Results; At 1 month of treatment, s-CTX was reduced by 54.8% (95% CI 40.4-59.8%) in the ZOL group (26 evaluable patients) compared with 38.2% (95% CI 29.8-48.7%) in the oral IBA group (27 evaluable patients) (p = 0.03). At 3 months, s-CTX was reduced by 72.6% (95% CI 58.6-71.3%) in the ZOL group, compared with 66.4% (95% CI 54.3-79.5%) in the oral IBA group (p = 0.22). Both bisphosphonates similarly decreased the bone marker B-ALP at 1 month (ZOL 24.7%, 95% CI 3.6-39.5%, and IBA 24.2%, 95% CI 2.8-43.4%) and 3 months (ZOL 28.6%, 95% CI 〈2.8-43.3%, and IBA 24.2%, 95% CI 3.2-47.4%). Both bisphosphonates were well tolerated. Conclusion; Considering the changes in bone markers, ZOL and oral IBA show comparable efficacy in patients with NSCLC and bone metastases.