Real-world effects, safety, and predictors of the effectiveness of romosozumab in primary and secondary osteoporosis: An observational study.

Romosozumab is an anti-sclerostin antibody that increases bone formation and decreases bone resorption. It became available for patients at high risk of osteoporotic fractures in Japan in 2019. The aim of this study was to clarify the clinical effects, safety, and predictors of the effectiveness of 12 months of romosozumab therapy. The study had an observational pre-post design and included 460 patients. Romosozumab was administered at a dose of 210 mg subcutaneously every 4 weeks for 12 months. The incidence of new fractures, safety, and changes in bone mineral density (BMD) and bone turnover markers were recorded. New fractures occurred in 11 cases (3.0 %). Nine patients (2.0 %) experienced cardiovascular events, which were fatal in 3 (0.65 %). Percent changes in BMD at the spine and total hip at 12 months from baseline were +7.7 % and +1.8 %, respectively. Romosozumab had better effects in patients with good renal function, low spine BMD, and high TRACP-5b at baseline and low TRACP-5b or high P1NP after 1 month of treatment. The percent change in spine BMD at 12 months was significantly lower in patients transitioning from denosumab than in those not previously treated with other anti-osteoporosis agents. Romosozumab is considered to be relatively safe in patients with primary osteoporosis compared to those with secondary osteoporosis. Romosozumab resulted in larger increases in spine BMD in patients with primary osteoporosis who were not previously treated with other anti-osteoporosis therapies and those with low spine BMD at the start of treatment.