Denosumab is a novel, fully human IgG2 monoclonal antibody specific to receptor activator of nuclear factor kappa-B ligand (RANKL), suppresses bone resorption markers in patients with a variety of metastatic tumors and is being investigated in multiple clinical trials for the prevention and treatment of bone metastases. Chemically, it consists of 2 heavy and 2 light chains. Each light chain consists of 215 amino acids. Each heavy chain consists of 448 amino acids with 4 intramolecular disulfides. FDA approved on June 1, 2010.