[Double-blinded controlled study comparing clodronate versus placebo in patients with breast cancer bone metastases]

One hundred forty-four patients with breast cancer and osteolytic bone metastases were randomized to receive either oral clodronate 1,600 mg/d (73 patients) or placebo (71 patients), in addition to either chemotherapy or hormonal therapy, for up to 12 months. Patients were withdrawn from the study when the 12 months of treatment had been achieve or a new bone event occurred, which was defined as: hypercalcemia (> 3 mmol/l), increase in, or onset of new bone pain due to metastases, requirement of radiotherapy for bone pain relief, pathological fractures (including vertebral collapse, spinal cord compression) or death due to bone metastases. Patients are well balanced according to age, performance status, bone condition, except for fractures, more frequent in the clodronate group (25% vs 12%). Of the 137 evaluable patients, 69 received oral clodronate and 68 placebo. Clodronate significantly delayed the median time to onset of new bone events compared to placebo, respectively 244 days and 180 days (p = 0.05). Hypercalcemia did not occur in the clodronate group but was observed in four placebo-treated patients. Clodronate-treated patients had a significant reduction in pain intensity compared to placebo (p = 0.01; measured using a visual pain scale) and significantly fewer patients receiving clodronate required analgesics (p = 0.02). The evaluation of global efficacy by physicians and patients indicated that clodronate was more efficacious than placebo (respectively p = 0.02 and p = 0.01). No significant difference in incidence of adverse effects was observed between the two groups. Clodronate therapy significantly delayed the occurrence of new bone events in these patients with bone metastases from breast cancer and adds to treatment of malignant osteolysis.