The Effects of Strontium Ranelate on the Risk of Vertebral Fracture in Women with Postmenopausal Osteoporosis

TLDR

Osteoporotic structural damage and bone fragility arise from reduced bone formation and increased bone resorption. The study aimed to evaluate whether oral strontium ranelate could reduce vertebral fracture risk and increase bone mineral density in postmenopausal women with osteoporosis. In a randomized, double‑blind, placebo‑controlled phase 3 trial, 1,649 women received 2 g/day of strontium ranelate or placebo for three years, with calcium and vitamin D supplementation, annual vertebral radiographs, and BMD measurements every six months. Strontium ranelate lowered vertebral fracture incidence by 49 % in the first year and 41 % over three years, increased lumbar spine BMD by 14.4 % and femoral neck BMD by 8.3 % at 36 months, and did not raise serious adverse events, confirming early and sustained fracture risk reduction.

Abstract

Osteoporotic structural damage and bone fragility result from reduced bone formation and increased bone resorption. In a phase 2 clinical trial, strontium ranelate, an orally active drug that dissociates bone remodeling by increasing bone formation and decreasing bone resorption, has been shown to reduce the risk of vertebral fractures and to increase bone mineral density.To evaluate the efficacy of strontium ranelate in preventing vertebral fractures in a phase 3 trial, we randomly assigned 1649 postmenopausal women with osteoporosis (low bone mineral density) and at least one vertebral fracture to receive 2 g of oral strontium ranelate per day or placebo for three years. We gave calcium and vitamin D supplements to both groups before and during the study. Vertebral radiographs were obtained annually, and measurements of bone mineral density were performed every six months.New vertebral fractures occurred in fewer patients in the strontium ranelate group than in the placebo group, with a risk reduction of 49 percent in the first year of treatment and 41 percent during the three-year study period (relative risk, 0.59; 95 percent confidence interval, 0.48 to 0.73). Strontium ranelate increased bone mineral density at month 36 by 14.4 percent at the lumbar spine and 8.3 percent at the femoral neck (P<0.001 for both comparisons). There were no significant differences between the groups in the incidence of serious adverse events.Treatment of postmenopausal osteoporosis with strontium ranelate leads to early and sustained reductions in the risk of vertebral fractures.