A RANDOMIZED PHASE-II STUDY OF ORAL PAMIDRONATE FOR THE TREATMENT OF BONE METASTASES FROM BREAST-CANCER

47 patients with progressive, painful, predominantly lyric bone metast ases from breast cancer were included in a randomised double-blind pha se II trial comparing the effects of pamidronate 150 and 300 mg daily. Oral pamidronate produced either sclerosis or stabilisation of lyric metastases for at least 24 weeks in 5 of 24 and 3 of 23 patients at th e 300 and 150 mg dose levels, respectively. Evidence of symptomatic im provement was observed in 5 of 22 (23%) and 7 of 22 (32%) patients for symptomatic disease at the respective doses. These improvements were accompanied by a reduction in the rate of bone resorption as shown by suppression (P=<0.01) of urinary calcium and a non-significant fall in deoxypyridinoline. No obvious differences in efficacy were observed b etween the two dose levels. Gastrointestinal adverse events, principal ly comprising nausea and vomiting, were the most commonly reported sid e-effects leading to discontinuation of trial treatment in 4 of 24 and 2 of 23 patients at 300 and 150 mg dose levels, respectively. The poo r tolerability of oral pamidronate coupled with the modest clinical ef fects reported here suggest that oral pamidronate will not replace the current strategy of regular intravenous infusions of pamidronate for the treatment of osteolytic bone disease. (C) 1998 Elsevier Science Lt d. All rights reserved.