THOUSAND OAKS, Calif., June 13, 2013 /PRNewswire/ -- Amgen (NASDAQ:AMGN) today announced that the U.S. Food and Drug Administration (FDA) has approved a new indication for XGEVA ® (denosumab) for the treatment of adults and skeletally mature adolescents with giant cell tumor of bone (GCTB) that is unresectable or where surgical resection is likely to result in severe morbidity. XGEVA was approved following a priority review by the FDA, a designation reserved for drugs that offer major advances in treatment, or provide a treatment where no adequate therapy exists. GCTB typically affects individuals between the ages of 20 to 40. The disease is characterized by a bone destructive tumor that often results in fractures. When untreated, it often results in complete destruction of the affected bone, leading to bone fracture, joint dysfunction, deformity or amputation. The approval of XGEVA is based on positive results from two open-label trials that enrolled patients with GCTB that was either recurrent, unresectable, or for which planned surgery was likely to result in severe morbidity. The overall objective response rate of the 187 patients evaluated was 25 percent. The estimated median time to response was three months. In the 47 patients with an objective response, 51 percent (24/47) had a duration of response lasting at least eight months. Three patients experienced disease progression following an objective response. The safety profile of XGEVA in patients with GCTB was similar to that reported in studies of patients with bone metastases, and also appeared to be similar in skeletally mature adolescents and adults. Safety data was evaluated in 304 patients with GCTB who received at least one dose of XGEVA. Of these patients, 145 were treated for at least one year. The most common adverse reactions were arthralgia, headache, nausea, back pain, fatigue, and pain in the extremity. The most common serious adverse reactions were osteonecrosis of the jaw and osteomyelitis.