This prospective observational study evaluated the effects of adding romosozumab to ongoing denosumab treatment in postmenopausal women with severe osteoporosis. The study included 52 women, divided into three groups: romosozumab alone (n=19), romosozumab combined with denosumab (n=11), and continued denosumab alone (n=22). Bone mineral density (BMD) was assessed at baseline and after 6 months, and serum samples were collected for bone turnover markers, bone modulators, and calcium phosphate metabolism. Key findings include: - BMD increased significantly at all sites in the romosozumab alone group (+6.1%, total hip +6.8%, lumbar spine +79%). - BMD increased only at the lumbar spine in the combination group (+2%) and in the denosumab group (+1.5%). - P1NP levels increased significantly in both romosozumab groups at month 3 (+70.4% in romosozumab alone, +99.1% in combination group). - Sclerostin levels increased steeply in both romosozumab groups, while Dkk1 levels did not change. The study concluded that adding romosozumab to ongoing denosumab treatment resulted in increased P1NP and lumbar spine BMD but not femoral neck BMD. Further randomized controlled trials are needed to confirm these results and explore fracture outcomes.This prospective observational study evaluated the effects of adding romosozumab to ongoing denosumab treatment in postmenopausal women with severe osteoporosis. The study included 52 women, divided into three groups: romosozumab alone (n=19), romosozumab combined with denosumab (n=11), and continued denosumab alone (n=22). Bone mineral density (BMD) was assessed at baseline and after 6 months, and serum samples were collected for bone turnover markers, bone modulators, and calcium phosphate metabolism. Key findings include: - BMD increased significantly at all sites in the romosozumab alone group (+6.1%, total hip +6.8%, lumbar spine +79%). - BMD increased only at the lumbar spine in the combination group (+2%) and in the denosumab group (+1.5%). - P1NP levels increased significantly in both romosozumab groups at month 3 (+70.4% in romosozumab alone, +99.1% in combination group). - Sclerostin levels increased steeply in both romosozumab groups, while Dkk1 levels did not change. The study concluded that adding romosozumab to ongoing denosumab treatment resulted in increased P1NP and lumbar spine BMD but not femoral neck BMD. Further randomized controlled trials are needed to confirm these results and explore fracture outcomes.