However, the results of recent Phase I-II studies suggest that 1-methyl-D-tryptophan (an inhibitor of the IDO pathway also known as indoximod), other pharmacological blockers of IDO1 (such as INCB024360), and IDO1-targeting vaccines are well tolerated by cancer patients and mediate antineoplastic effects, at least in a subset of individuals [376-382]. This evidence concerns the gene IDO1 and cancer.