Surprisingly, the rate of grade 3 or greater toxicity observed in this combination study (39.4%) was lower than that seen with the combinations of axitinib plus pembrolizumab (71.2%) and axitinib plus avelumab (62.9%) in RCC.41,42 Multiple factors might contribute to this difference, including differences in histology between mucosal melanoma and RCC; ethnicity, which may influence tolerance of VEGF therapy; and the higher dose of axitinib used in a minority of patients in the other studies. This evidence concerns the gene VEGFA and mucosal melanoma.