Increased bone mineral density for 1 year of romosozumab, vs placebo, followed by 2 years of denosumab in the Japanese subgroup of the pivotal FRAME trial and extension.

Romosozumab, which binds sclerostin, rebuilds the skeletal foundation before transitioning to antiresorptive treatment. This subgroup analysis of an international, randomized, double-blind study in postmenopausal women with osteoporosis showed efficacy and safety outcomes for romosozumab followed by denosumab in Japanese women were generally consistent with those for the overall population. PURPOSE: In the international, randomized, double-blind, phase 3 FRActure study, in postmenopausal woMen with ostEoporosis (FRAME; NCT01575834), romosozumab followed by denosumab significantly improved bone mineral density (BMD) and reduced fracture risk. This report evaluates Japanese women in FRAME. METHODS: Postmenopausal women with osteoporosis (T-score - 3.5 to - 2.5 at total hip or femoral neck) received romosozumab 210 mg or placebo subcutaneously monthly for 12 months, then each group received denosumab 60 mg subcutaneously every 6 months for 24 months. The key endpoint for Japanese women was BMD change. Other endpoints included new vertebral, clinical, and nonvertebral fracture; the subgroup analysis did not have adequate power to demonstrate statistically significant reductions. RESULTS: Of 7180 enrolled subjects, 492 (6.9%) were Japanese (247 romosozumab, 245 placebo). BMD increases from baseline were greater (P < 0.001) for romosozumab-to-denosumab than placebo-to-denosumab at the lumbar spine (36 months, 12.7%), total hip (4.2%), and femoral neck (4.1%). Fracture risk was lower through 36 months for romosozumab-to-denosumab vs placebo-to-denosumab for new vertebral (1.7% vs 4.5%; relative risk reduction (RRR) 63%, P = 0.070), clinical (3.2% vs 7.3%; RRR 53%, P = 0.072), nonvertebral (2.8% vs 6.1%; RRR 50%, P = 0.12), and all other fracture types evaluated. Rates of adverse events and positively adjudicated serious cardiovascular events were generally balanced between groups. CONCLUSIONS: Efficacy and safety for romosozumab-to-denosumab were similar between Japanese women and the overall population. The sequence of romosozumab to rebuild the skeletal foundation before transitioning to antiresorptive treatment with denosumab is a promising regimen for Japanese postmenopausal women with osteoporosis at high risk of fracture.

One Year of Romosozumab Followed by Two Years of Denosumab Maintains Fracture Risk Reductions: Results of the FRAME Extension Study.

Romosozumab, a humanized monoclonal antibody that binds and inhibits sclerostin, has the dual effect of increasing bone formation and decreasing bone resorption. As previously reported in the pivotal FRActure study in postmenopausal woMen with ostEoporosis (FRAME), women with a T-score of ≤ -2.5 at the total hip or femoral neck received subcutaneous placebo or romosozumab once monthly for 12 months, followed by open-label subcutaneous denosumab every 6 months for an additional 12 months. Upon completion of the 24-month primary analysis period, eligible women entered the extension phase and received denosumab for an additional 12 months. Here, we report the final analysis results through 36 months, including efficacy assessments of new vertebral, clinical, and nonvertebral fracture; bone mineral density (BMD); and safety assessments. Of 7180 women enrolled, 5743 (80%) completed the 36-month study (2851 romosozumab-to-denosumab; 2892 placebo-to-denosumab). Through 36 months, fracture risk was reduced in subjects receiving romosozumab versus placebo for 12 months followed by 24 months of denosumab for both groups: new vertebral fracture (relative risk reduction [RRR], 66%; incidence, 1.0% versus 2.8%; p < 0.001), clinical fracture (RRR, 27%; incidence, 4.0% versus 5.5%; p = 0.004), and nonvertebral fracture (RRR, 21%; incidence, 3.9% versus 4.9%; p = 0.039). BMD continued to increase for the 2 years with denosumab treatment in both arms. The substantial difference in BMD achieved through 12 months of romosozumab treatment versus placebo was maintained through the follow-up period when both treatment arms received denosumab. Subject incidence of adverse events, including positively adjudicated serious cardiovascular adverse events, were overall balanced between groups. In conclusion, in postmenopausal women with osteoporosis, 12 months of romosozumab led to persistent fracture reduction benefit and ongoing BMD gains when followed by 24 months of denosumab. The sequence of romosozumab followed by denosumab may be a promising regimen for the treatment of osteoporosis. © 2018 American Society for Bone and Mineral Research.