Predictive Value of Bone Resorption and Formation Markers in Cancer Patients With Bone Metastases Receiving the Bisphosphonate Zoledronic Acid

Abstract
Purpose Three large, randomized trials of patients with bone metastases recently demonstrated that zoledronic acid reduces the risk of skeletal-related events. These trials provide an opportunity for investigating the correlation between bone metabolism and clinical outcome during bisphosphonate therapy. Patients and Methods Urinary measurements of N-telopeptide (Ntx) and serum bone alkaline phosphatase (BAP) were obtained in 1,824 bisphosphonate-treated patients—1,462 with zoledronic acid (breast, 490; prostate, 411; myeloma, 210; non–small-cell lung, 183; other, 168) and 362 with pamidronate (breast, 254; myeloma, 108). This exploratory cohort analysis grouped patients by baseline and most recent levels of Ntx as low (< 50 nmol/mmol creatinine), moderate (50 to 99 nmol/mmol creatinine), or high (≥ 100 nmol/mmol creatinine), and BAP as low (< 146 U/L) or high (≥ 146 U/L). The relative risks for negative clinical outcomes were estimated for each group using multiple-event and Cox regression models with ti...