Real-world effects and adverse events of romosozumab in Japanese osteoporotic patients: A prospective cohort study

Real-world data on the new anti-sclerostin antibody drug, romosozumab, remain scarce. There is a strong need to accumulate and analyze data on romosozumab treatment for such conditions as osteoporosis. The purpose of this study was to investigate the therapeutic and adverse effects of romosozumab for osteoporosis treatment in clinical practice. Of the 230 osteoporosis patients prescribed romosozumab from September 2019 in this prospective multicenter cohort study, 204 patients completed 12 months of treatment. The primary outcome of interest was the rate of change in bone mineral density (BMD) of the lumbar spine, total hip, and femoral neck as measured by dual-energy X-ray absorptiometry. Secondary outcomes included changes in bone turnover markers and serum-corrected calcium level as well as the incidence of adverse events. At 6 and 12 months of romosozumab treatment, the respective percentage change in BMD from baseline was 7.4% and 12.2% for the lumbar spine, 1.8% and 5.8% for the total hip, and 2.9% and 6.0% for the femoral neck, all of which were significantly higher (P < 0.001) than baseline values. Patients who switched from another osteoporosis regimen exhibited significantly lower lumbar spine BMD gains versus treatment-naïve patients, especially for cases switching from denosumab. P1NP was significantly increased at 6 months (58.9%; P < 0.01), while TRACP-5b was significantly decreased at 6 months (−14.7%; P < 0.001) and 12 months (−18.8%; P < 0.001) versus baseline values. The largest rate of decrease in serum-corrected calcium was 3.7% at 12 months. Sixty-four (27.8%) of 230 patients experienced an adverse event, and 7 (3.0%) new fractures were recorded. In sum, romosozumab treatment for 12 months significantly improved lumbar spine, total hip, and femoral neck BMD according to real-world data.