Randomised, placebo-controlled multicentre trial of clodronate in multiple myeloma. Finnish Leukaemia Group.

Osteolytic lesions and pathological fractures are common in multiple myeloma. Because clodronate inhibits osteoclastic resorption, we did a randomised, controlled trial in 350 patients from 23 hospitals. All patients received standard melphalan-prednisolone, and were randomised to receive clodronate 2.4 g daily or placebo for 24 months. The proportion of patients with progression of osteolytic bone lesions was twice as high in the placebo group (n = 168 at baseline) than in the clodronate group (n = 168 at baseline) in an intention-to-treat analysis (24 vs 12%, p = 0.026). Progression of vertebral fractures was lower in the clodronate group, but the difference was not significant (30 vs 40%). Serum calcium and urinary calcium excretion decreased significantly in both groups, but the changes were greater in the clodronate group. The percentage of patients feeling no pain increased more in the clodronate group (from 24 to 54%, p < 0.001) than in the placebo group (from 29 to 44%, p < 0.01). Side-effects were similar in both groups. We conclude that clodronate is an effective and safe adjunct in the management of multiple myeloma. The drug delays osteolytic bone lesions, reduces the degree of hypercalcaemia and hypercalciuria, and decreases pain.