Long-term effects of dichloromethylene diphosphonate (CI2MDP) on skeletal lesions in multiple myeloma.

We report the long-term effects of dichloromethylene diphosphonate (CI2MDP), an inhibitor of bone resorption, on the skeletal lesions in multiple myeloma. Thirteen patients received either CI2MDP 1600 mg/d (seven patients) or a placebo (six patients) in addition to other chemotherapy, and the effects of treatment were followed over a period of up to 18 months in a double-blind study. CI2MDP treatment resulted in a marked reduction in bone pain, with no progression of radiologic skeletal lesions during the first year. This contrasted with a clinical deterioration and the occurrence of new fractures in half of the patients receiving the placebo. Two patients with hypercalciuria and increased excretion of hydroxyproline before treatment had normalized values following CI2MDP. Finally, iliac crest bone biopsies showed a reduction in osteoclast number after CI2MDP administration. We conclude from these results that CI2MDP could be of use in preventing the bone loss that occurs in multiple myeloma.