Pamidronate in the treatment of bone metastases: results of 2 dose-ranging trials in patients with breast or prostate cancer.

Four intravenous regimens of pamidronate (Aredia) were evaluated for palliative treatment of bone metastases in 2 randomized open-label trials in patients with breast cancer (n = 61) or prostate cancer (n = 58). In breast cancer patients, administration of pamidronate 60 mg every 4 weeks, 60 mg every 2 weeks, or 90 mg every 4 weeks for 3 months resulted in statistically and clinically significant reductions in bone pain, with accompanying decreases in biochemical markers of bone turnover; a regimen of 30 mg every 2 weeks was not effective. Healing of bone lesions was observed in 25% of breast cancer patients. In prostate cancer patients, the same regimens of pamidronate produced reductions in bone pain, but no dose-response relationship was apparent. Moreover, there were no consistent changes in biochemical indices in these patients, and no healing of bone lesions occurred. The different response to pamidronate in those 2 patient populations may reflect the different severity of metastatic disease at baseline. Side effects of pamidronate were mild and transient in both studies.