The analgesic efficacy of clodronate compared with placebo in patients with painful bone metastases from prostatic cancer.

Fifty-five patients with hormone refractory prostate cancer and painful bone metastases were randomised either to placebo or to clodronate 300 mg i.v. for 3 days, followed by oral clodronate 3200 mg for four weeks. Pain intensity was assessed using Visual Analogue Scales (VAS). Mean overall pain as well as mean pain during the best and worst periods were recorded. Forty-six patients were evaluable for efficacy. No significant differences were found between the two treatments. As regards mean worst pain a substantial numerical fall was registered for the treatment group, 21 mm, but the improvement was not significant compared to that of the placebo group. This was probably due to the limited number of patients (the study was prematurely ended due to problems recruiting patients). In conclusion, no significant differences were found between the treatment arm and the controls, in contrast to results from previous studies. Possible explanations are that the doses in this study were generally lower than in previous studies, the mean baseline pain was substantially lower and that the current study was placebocontrolled. Our data indicate that if clodronate is to be used for the alleviation of bone pain in prostate cancer, patients with high baseline should be selected and high intravenous doses should be given at start of the treatment.