CTLA4 and melanoma: However, even the sole administration of ICIs results in severe colitis in fewer than <1% of patients, as shown in checkmate 037 and checkmate 066 (both melanoma trials using nivolumab) [15] and checkmate 017 in SQ-NSCLC (nivolumab) [3] and mentioned in treatment with anti-CTLA-4 antibody.