In 2013, the US FDA approved Xgeva (denosumab, denosumab), manufactured by Amgen, for the treatment of recurrent and refractory giant cell tumors of bone in adults and certain adolescents. Xgeva was first approved in the United States in 2010 for use in patients with bone metastases from solid tumors to prevent skeletal-related events, and was approved in Europe in 2011 for the same indication. A Phase II clinical trial conducted by the FDA prior to its approval for the treatment of giant cell tumor of bone showed no significant disease progression in 163 patients at an average follow-up of 10 months in 169 patients. Another phase II trial showed that 74% of 100 patients treated who would have been severely disabled if surgery had been performed avoided surgery, and 16 of 26 patients who had surgery had significantly less disability after surgery than expected before surgery.