Effect of oral clodronate on metastatic bone pain: a double-blind, placebo-controlled study

To study the effects of oral clodronate on bone pain in patients with advanced metastatic bone disease.

Fifty-five patients with progressing bone metastases were randomized to receive oral clodronate 1,600 mg/d (n = 27) or matching placebo (n = 28). The main outcome measures were bone pain (visual analog score), analgesic use, and compliance with therapy.

Visual analog pain score (median [interquartile range]) decreased from the pretreatment value in the clodronate group (-0.9 [-2.6 to -0.4]), but increased in the placebo group (+0.4 [-1.0 to +4.0]) (P = .03 between groups). Analgesic use increased with disease progression to a similar extent in both groups (59% increased use in the clodronate group v 64% of placebo group; difference not significant). Ten patients (37%) in the clodronate group and 12 (46%) in the placebo group withdrew from the study prematurely, most often because of difficulty with swallowing the capsules.

Clodronate improved control of bone pain to a modest degree in patients with advanced metastatic cancer, but did not reduce analgesic requirement significantly. Perhaps as a result of these factors, it proved difficult to maintain patients on therapy. Further studies will be needed to define the role of bisphosphonates such as clodronate in this situation, in comparison with established treatments such as radiotherapy and analgesics.