Strontium ranelate: an increased bone quality leading to vertebral antifracture efficacy at all stages

Strontium ranelate is a new antiosteoporotic treatment with a dual mode of action, both increasing bone formation and decreasing bone resorption, which rebalances bone turnover in favor of bone formation and increases bone strength. The antifracture efficacy of strontium ranelate, 2 g per day orally, in the treatment of postmenopausal osteoporosis has been investigated in a large-scale, international, multicenter, phase 3 program in which more than 7000 patients were recruited. This article deals with the vertebral antifracture efficacy of strontium ranelate in postmenopausal women with osteoporosis. A significant early (after 1 year) and sustained (over 3 years) antifracture efficacy of strontium ranelate, compared with placebo, was demonstrated in patients with prevalent vertebral fracture with reductions in risk of new vertebral fracture of 49% after 1 year (P < 0.001) and 41% over 3 years (P < 0.001). In addition, the relative risk of clinical vertebral fracture was significantly reduced by 52% (P = 0.003) after 1 year and by 38% (P < 0.001) over 3 years in the strontium ranelate group compared with placebo. Strontium ranelate was also demonstrated to significantly decrease the relative risk of vertebral fractures by 45% (P < 0.001) in patients without prevalent vertebral fracture over 3 years, vs. placebo. Bone mineral density was linearly increased during 3 years of treatment with strontium ranelate in comparison with placebo. Strontium ranelate was well tolerated throughout the entire duration of the clinical trials. Thus, strontium ranelate, 2 g per day orally, is a new, effective, and safe treatment for postmenopausal patients with osteoporosis, to reduce the vertebral fracture risk in patients with or without a history of vertebral fracture.