Efficacy and safety of 2 g/day of strontium ranelate in Asian women with postmenopausal osteoporosis.

Abstract

Strontium ranelate is a new effective anti-osteoporotic treatment having a unique mode of action, reducing bone resorption while promoting continued bone formation, with a broad range of anti-fracture efficacy at vertebral as well as peripheral sites. In Phase III studies, it has proven its early and sustained efficacy against vertebral fractures in Caucasians along with a significant increase in lumbar bone mineral density (BMD). The aim of this randomized double-blind study was to demonstrate the efficacy of strontium ranelate (2 g/day) on lumbar spine bone mineral density and the clinical and biological safety in Asian postmenopausal osteoporotic patients compared to placebo over 1 year. Three hundred and twenty-nine eligible women from mainland China, Hong Kong and Malaysia were randomized into the study. The baseline characteristics were similar in the treatment and placebo groups: mean age of 66.2+/-6.5 years, time since menopause 17.6+/-7.2 years. In the Full Analysis Set (FAS, N=302), the mean baseline lumbar L2-L4 BMD was 0.715+/-0.106 g/cm(2) in the strontium ranelate group and 0.708 +/- 0.109 g/cm2 in the placebo group. The mean baseline femoral neck BMD was 0.575+/-0.074 g/cm2 and 0.566+/-0.069 g/cm2 respectively and mean total hip BMD was 0.642+/-0.080 g/cm2 and 0.631 +/-0.088 g/cm2 respectively. The overall compliance was 91.4% in the study drug group, and 97.4% in the placebo group. After 1 year of treatment, the lumbar spine, femoral neck and total hip BMD in the treated group was significantly increased by 3-5% as compared to placebo. Strontium ranelate was well tolerated. The most frequently reported emergent adverse events were comparable in both groups (60.4% versus 60.0%), with majority of them being mild gastrointestinal disorders. There were no clinically relevant changes in laboratory tests, such as blood routine, hepatic and renal function. It is thus concluded that the effects of 2 g/day strontium ranelate on BMD and its safety profile in this cohort of postmenopausal osteoporotic Asian women were consistent with results obtained from Caucasian women in which the efficacy on the reduction in risk of fracture has been proven.