A drug used to prevent or treat certain bone problems. It is used under the brand name Xgeva to prevent bone problems caused by multiple myeloma or by solid tumors that have spread to the bone. It is also used in certain patients to treat giant cell tumor of the bone that cannot be removed by surgery, and to treat hypercalcemia that is caused by cancer and did not get better after treatment with bisphosphonates. Denosumab is also used under the brand name Prolia to increase bone mass in certain patients with breast cancer or prostate cancer who have a high risk of breaking bones. It is also used to treat osteoporosis in men and postmenopausal women who have a high risk of breaking bones. Denosumab is also being studied in the treatment of other conditions and types of cancer. It binds to a protein called RANKL, which keeps RANKL from binding to another protein called RANK on the surface of certain bone cells, including bone cancer cells. This may help keep bone from breaking down and cancer cells from growing. Denosumab may also prevent the loss of calcium from the bones. It is a type of monoclonal antibody. Also called AMG 162.