A retrospective analysis of human leukocyte antigen (HLA) subtypes from four phase II trials (n = 453) in advanced melanoma patients treated with ipilimumab was conducted. Patients were randomized to 0.3, 3 or 10 mg/kg ipilimumab in the trials. The median overall survival was similar for 187 HLA-A*021-positive patients and for 266 HLA-A*021-negative patients (9.3 vs. 11.4 months, respectively) for all doses. These were similar to results from a phase III ipilimumab study in HLA-positive patients with an overall survival of 10.1 months. Adverse events were similar in HLA-positive and -negative patients and among phase II and phase III patients. Advanced melanoma outcome thus appeared to be similar with ipilimumab irrespective ...