Strontium Ranelate Reduces the Risk of Nonvertebral Fractures in Postmenopausal Women With Osteoporosis: Treatment of Peripheral Osteoporosis (TROPOS) Study

Abstract

Strontium ranelate is an orally active drug that may permit ongoing production of bone while at the same time reducing bone resorption. New vertebral fractures reportedly are less frequent in postmenopausal women who receive this agent. The Treatment of Peripheral Osteoporosis Study (TROPOS) is a randomized, double-blind, placebo-controlled trial designed to show whether strontium ranelate prevents nonvertebral fractures in European and Australian postmenopausal women who had a bone mineral density (BMD) equivalent to a T-score less than −2.5. Participants were 74 years or older, or 70 to 74 years if an additional fracture risk factor was present. Either strontium ranelate in a daily dose of 2 g or placebo was given to 5091 postmenopausal women with osteoporosis. Major statistical analysis was undertaken over 3 years of treatment. The intention-to-treat population totaled 4932 patients. The relative risk (RR) of nonvertebral fractures was reduced 16% during 3 years of follow up, and major nonvertebral osteoporotic factors were reduced by 19%. The RR for hip fracture was reduced by 15%—not a statistically significant result. Hip fractures were reduced 36% in women aged 74 years and older who had a BMD T-score of −3 or less. Patients given strontium ranelate had a 39% reduction in the RR of new vertebral fractures over 3 years. The RR of a first vertebral fracture was lowered by 45%. BMD increased significantly in both the total hip and femoral neck. Treatment was well-tolerated, and changes in serum levels of calcium, phosphorus, and parathyroid hormone were not of clinical importance. Nonvertebral fractures, particularly hip fractures, are significantly less likely to occur in postmenopausal women with osteoporosis who receive 2 g of strontium ranelate daily compared with placebo recipients. The investigators believe that this drug could be a helpful first-line treatment for postmenopausal osteoporosis.