Romosozumab

Romosozumab is a humanized monoclonal antibody that targets sclerostin, a protein produced by osteocytes that inhibits Wnt signaling. By binding to sclerostin, romosozumab enhances bone formation while simultaneously reducing bone resorption, leading to increases in bone mineral density and a lower risk of fracture.

Medical use and administration: Romosozumab is indicated for the treatment of postmenopausal osteoporosis in women at high risk for fracture, particularly those who have failed other osteoporosis therapies or are intolerant to them. It is given as a 210 mg subcutaneous injection once a month for 12 consecutive months. After completing the 12-month course, therapy is typically continued with an antiresorptive agent such as a bisphosphonate or denosumab to maintain gains in bone density and fracture protection.

Efficacy: In clinical trials, romosozumab increased spine and hip BMD and reduced vertebral fractures during the 12-month treatment period. In head-to-head and sequence studies, it demonstrated superior fracture risk reduction when followed by antiresorptive therapy, though results varied by fracture site and patient population.

Safety and regulatory status: A boxed warning highlights an increased risk of major adverse cardiovascular events (including myocardial infarction and stroke) in some patients, leading regulators to restrict use to those at high fracture risk who do not have significant cardiovascular risk. Common adverse effects include injection-site reactions, joint/muscle pain, headaches, and edema. In the United States, romosozumab is marketed as Evenity by Amgen and was approved for osteoporosis treatment in 2019; approvals and labeling vary by region, with ongoing monitoring of cardiovascular safety recommendations.

See also: osteoporosis, sclerostin inhibitors, antiresorptives.