Denosumab is a fully human monoclonal antibody that specifically targets a ligand known as RANKL (that binds to a receptor known as RANK) which is a key mediator of osteoclast formation, function, and survival. Denosumab was approved for the treatment of postmenopausal women with osteoporosis at high risk for fracture (history of osteoporotic fracture, multiple risk factors for fracture) or patients who have failed or are intolerant of other available osteoporosis therapies. Denosumab inhibits the formation, function, and survival of osteoclasts. It decreases bone resorption, increases bone mineral density (BMD), and reduces the risk of fracture.