Positive effects of zoledronate on skeletal-related events in patients with renal cell cancer and bone metastases.

INTRODUCTION: Approximately 30% of patients with renal cell cancer (RCC) develop bone metastasis causing skeletal-related events (SRE): pathologic fracture, spinal cord compression, surgery to bone and radiotherapy. Zoledronic acid demonstrated significant clinical benefit in RCC patients in a retrospective analysis. Primary objective of this prospective study was the proportion of patients experiencing ≥ 1 SRE during 12 months of zoledronic acid treatment and to verify the retrospective data. MATERIALS AND METHODS: Fifty patients with histologically confirmed RCC and evidence of ≥ 1 cancer-related bone lesion and ≤ 3 prior bisphosphonate applications were enrolled in 19 German centers between 2004 and 2007. The patients received 4 mg zoledronic acid every 3 weeks for 12 months followed by a follow up period for overall survival of 12 months. Bone lesions were diagnosed by bone scan or MRI-quickscan. Greater and equal to 1 lesion had to be confirmed by x-ray, CT or MRI scan. Additional bone scans were performed after completion of study treatment and if clinically indicated. In case of suspicion or evidence of a SRE it had to be confirmed radiologically. RESULTS: In total, 49 of the 50 enrolled patients were treated. Only 11 of them (22.4%) experienced any SRE until month 12. Patients with > 6 lesions and higher baseline MSKCC (Memorial Sloan-Kettering Cancer Center) score had a higher risk for SREs. Zoledronic acid was generally well tolerated and its known safety profile was affirmed. CONCLUSIONS: This prospective study confirms the results of prior data about the efficacy of zoledronic acid in patients with metastatic (m)RCC, supporting its beneficial use in these patients.

The ZOTECT study: Effect of zoledronic acid on bone metabolism in patients with bone metastases from prostate or breast cancer.

PURPOSE: The ZOTECT study assesses the effect of zoledronic acid (ZOL) on bone-marker levels and potential correlations with disease outcomes in bisphosphonate-naive patients. METHODS: This prospective, single-arm, open-label study in bisphosphonate-naive (≥6 months) patients with bone metastases from prostate cancer (PC; n=301) or breast cancer (BC; n=99) enrolled at 98 German sites (May 2006 to July 2008) investigated the effect of ZOL (4 mg intravenously every 4 weeks×4 months, with a final follow-up at 12 months) on bone-marker levels. Secondary assessments: skeletal-related event (SRE) rate, pain, quality of life (QoL), and prostate-specific antigen levels. Endpoints were assessed using summary statistics by visit/tumor type and Kaplan-Meier analyses. RESULTS: ZOL treatment significantly decreased bone-marker levels (amino-terminal propeptide of type I collagen [P1NP], C-terminal cross-linking telopeptide of type I collagen [CTX]; P<0.0001), and this decrease was maintained through the final 1-year follow-up visit. Baseline P1NP and CTX levels correlated with extent of bone disease (P<0.0001, each) and on-treatment decreases in marker levels. Skeletal disease burden and bone-marker levels were similar between PC and BC patients, and ZOL did not significantly influence osteoprotegerin/receptor activator of nuclear factor-κB ligand levels. Only 13 SREs occurred in 11 patients, supporting the known ZOL-mediated reduction in SREs. On-treatment bone-marker level changes did not correlate with SRE rate, pain scores, or QoL. Generally, ZOL was well tolerated and adverse events were consistent with its known safety profile. CONCLUSIONS: This study confirms that ZOL therapy significantly reduces bone turnover (measured as P1NP and CTX levels) in patients with bone metastases from PC or BC.