Zoledronic acid versus pamidronate in the treatment of skeletal metastases in patients with breast cancer or osteolytic lesions of multiple myeloma: a phase III, double-blind, comparative trial.

PURPOSE: Zoledronic acid, a new and more potent bisphosphonate, was compared with pamidronate, the current standard treatment for patients with osteolytic or mixed bone metastases/lesions. PATIENTS AND METHODS: A total of 1,648 patients with either Durie-Salmon stage III multiple myeloma or advanced breast cancer and at least one bone lesion were randomly assigned to treatment with either 4 or 8 mg of zoledronic acid via 15-minute intravenous infusion or 90 mg of pamidronate via 2-hour intravenous infusion every 3 to 4 weeks for 12 months. The primary efficacy endpoint was the proportion of patients experiencing at least one skeletal-related event over 13 months. RESULTS: The proportion of patients with at…