Treatment of Postmenopausal Osteoporosis: Focus on Strontium Ranelate

Abstract

Given its increasing incidence and serious complications, osteoporosis requires safe and effective long-term treatment. Strontium ranelate (SR), a new anti-osteoporotic treatment with a unique mode of action, has been investigated in the Spinal Osteoporosis Therapeutic Intervention (SOTI) and the Treatment Of Peripheral OSteoporosis (TROPOS) trials, two major 3-year multinational placebo-controlled Phase III randomized clinical trials. In SOTI, SR treatment reduced the risk of vertebral fracture by 41% (20.9% vs. 32.8%, P < 0.001); in TROPOS, it reduced the risk of non-vertebral fracture by 16% (11.2% vs. 12.9%, P = 0.04), and the risk of hip fracture in patients at high risk by 36% (4.3% vs. 6.4%, P = 0.046). Also SR has been shown to decrease the risk of vertebral fracture after 4 years of treatment and the risk of nonvertebral fracture after 5 years. Also it demonstrated for high risk patients a significant decrease of the risk of hip fractures (–43%) after 5 years of treatment. Unlike antiresorptive agents, SR produced steady and significant BMD increases that correlated directly with decreases in vertebral and hip fracture risk. Preplanned analysis of the pooled dataset from SOTI and TROPOS showed that SR was effective whether or not patients had key risk factors for fractures at baseline. SR was also effective in patients with osteopenia and younger postmenopausal patients aged 50–65 years. It was also effective for preventing both vertebral and nonvertebral fractures in the elderly (>80 years). Also, SR significantly attenuated height loss and decreased back pain. Finally long-term follow-up showed that BMD gains were maintained through a 8 year-period with maintaining the incidence of fracture between the first 3 years and the last 3 years of treatment. The safety profile of SR was almost similar to placebo in both trials. A slight but significant increased risk of thromboembolism events was noted from the pooled phase III studies data. However this increased was not found in a large retrospective observational study. Thus, SR demonstrates broad spectrum safety and efficacy in reducing the risks of both vertebral and non-vertebral (including hip) fractures in a wide variety of patients, and should be considered as a first-line option to treat women at risk of osteoporotic fractures, whatever their age, the severity of the disease, and their risk factors.