Biotechnology giant Amgen Inc. (AMGN) announced Thursday that the U.S. Food and Drug Administration has approved Xgeva or denosumab, a subcutaneous RANK Ligand inhibitor, for the treatment of bone metastases to reduce skeletal related events in patients with cancer. The treatment is poised to be a blockbuster for Amgen, with a potential to fetch $2.5 billion in global sales by the middle of the ...