CTLA4 and melanoma: In 2010, a CTLA-4-specific Immunoglobulin G1 (IgG1) monoclonal antibody, ipilimumab, was the first drug of any kind in history to provide a survival advantage in patients with advanced melanoma [3], and it was then approved by the Food and Drug Administration (FDA) in 2011 for the treatment of metastatic melanoma.