A new treatment for post-menopausal osteoporosis: strontium ranelate

Strontium ranelate is a new anti-osteoporotic agent which appears to reduce bone resorption by decreasing osteoclast differentiation and activity, and to stimulate bone formation by increasing replication of pre-osteoblast cells, leading to increased matrix synthesis. This review examines both the scientific rationale for its use in post-menopausal osteoporosis and the evidence of its antifracture efficacy. In the placebo-controlled, phase III trial Spinal Osteoporosis Therapeutic Intervention (SOTI) (no.=1442; mean age 69 yr), there was a 41% decrease over 3 yr in the number of patients with new vertebral fracture in the strontium ranelate (2 g/day) group vs placebo (p<0.001), and a 14.4% difference in lumbar bone mineral density (BMD) at 3 yr vs placebo. This reduction in vertebral fracture risk was already detected after 12 months (49% lower risk, p<0.001). The phase III TReatment Of Peripheral OSteoporosis (TROPOS) study assessed the efficacy of strontium ranelate (2 g/day) in preventing non-vertebral fracture in post-menopausal osteoporosis (no.=4932; mean age 77 yr). Strontium ranelate reduced non-vertebral fracture risk by 16% vs placebo (p=0.04) and hip fracture risk by 36% (p=0.031), in osteoporotic patients older than 74 yr. There was a concomitant increase in BMD throughout the study, reaching +8.2% (femoral neck) and +9.8% (total hip) at 3 yr. Strontium ranelate is thus a first-choice treatment of post-menopausal osteoporosis as it significantly reduces vertebral, non-vertebral and hip fracture risk in post-menopausal osteoporotic women, as well as having an excellent tolerability profile.