A double-blind, crossover trial of intravenous clodronate in metastatic bone pain

After a baseline symptom and laboratory assessment, 24 patients with metastatic bone disease and pain were randomized to receive either a 4-hr intravenous infusion of 2-dichloromethylene bisphosphonate (Cl₂MDP), 600 mg in 500 mL of normal saline, or a 4-hr placebo infusion, 500 mL of normal saline. The administration was double blind. After 1 wk, the assessment was repeated and the patients were crossed over to the alternate treatment. After 1 more wk, a final assessment and blinded choice by the patient and investigator took place. Of the 21 evaluable patients, 12 (57%) chose the Cl₂MDP and 4 (19%) chose the placebo; 5 (24%) patients did not have a specific preference (p = NS). The investigator chose the Cl₂MDP in 14 (67%) cases, placebo in 6 (29%) cases and was unable to discern a difference in 1 (5%) case (p < 0.05). The patients and investigator made similar selections in 16 (76%) instances. On the visual analogue scale assessments, a significant decrease in pain scores was observed following the Cl₂MDP infusion (p < 0.01) and an increase in activity scores was also demonstrated (p < 0.01). No significant difference in the daily oral morphine equivalent analgesic requirement was demonstrated for either arm. No difference in clinical and laboratory parameters of toxicity was evident between the placebo and Cl₂MDP arms of the trial Our preliminary findings suggest that Cl₂MDP is safe, and has analgesic properties that may prove to be useful in the management of metastatic bone pain.