Romosozumab in Postmenopausal Women with Low Bone Mineral Density

Background Sclerostin is an osteocyte-derived inhibitor of osteoblast activity. The monoclonal antibody romosozumab binds to sclerostin and increases bone formation. Methods In a phase 2, multicenter, international, randomized, placebo-controlled, parallel-group, eight-group study, we evaluated the efficacy and safety of romosozumab over a 12-month period in 419 postmenopausal women, 55 to 85 years of age, who had low bone mineral density (a T score of −2.0 or less at the lumbar spine, total hip, or femoral neck and −3.5 or more at each of the three sites). Participants were randomly assigned to receive subcutaneous romosozumab monthly (at a dose of 70 mg, 140 mg, or 210 mg) or every 3 months (140 mg or 210 mg), subcutaneous placebo, or an open-label active comparator — oral alendronate (70 mg weekly) or subcutaneous teriparatide (20 μg daily). The primary end point was the percentage change from baseline in bone mineral density at the lumbar spine at 12 months. Secondary end points included percentage ch...