The Effect of 1 Year of Romosozumab on the Incidence of Clinical Vertebral Fractures in Postmenopausal Women With Osteoporosis: Results From the FRAME Study

Abstract

Radiographic vertebral fractures (VFxs) are the most common fractures in osteoporosis and are associated with increased morbidity, mortality, and costs. A subset of VFxs manifest clinically, usually with a sudden onset of severe back pain. Romosozumab is a monoclonal antibody that binds and inhibits sclerostin, increasing bone formation and decreasing bone resorption, leading to rapid and large increases in bone density and strength and reduction in fracture risk. The FRAME (Fracture Study in Postmenopausal Women with Osteoporosis) study of postmenopausal women with osteoporosis demonstrated a significant reduction in new VFxs with romosozumab versus placebo. Here, we report the effect of romosozumab versus placebo on clinical VFx incidence over 12 months in women reporting back pain suggestive of VFxs. FRAME enrolled 7180 postmenopausal women with osteoporosis, mean age 70.9 years (hip T‐score −2.5 to −3.5). In the first year of the study, women received monthly romosozumab 210 mg (n = 3589) or placebo (n = 3591). At regular monthly visits, women reporting back pain suggestive of a clinical VFx had a confirmatory spine X‐ray. Clinical VFx risk in the romosozumab group versus the placebo group was calculated by Cox‐proportional hazards model. Of 119 women in FRAME with back pain suggestive of a clinical VFx over 12 months, 20 were confirmed to have experienced a new/worsening VFx. Three women receiving romosozumab had a clinical VFx (<0.1% of 3589 women) versus 17 (0.5% of 3591 women) receiving placebo resulting in a reduction in clinical VFx risk of 83% in the romosozumab group versus placebo through 12 months (HR 0.17; 95% CI, 0.05 to 0.58; p = 0.001). In the three romosozumab‐treated women, clinical VFxs occurred within the first 2 months of the study with no further clinical VFxs throughout the year. Romosozumab treatment for 12 months was associated with rapid and large reductions in clinical VFx risk versus placebo. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.