Selective inhibitor of IDH1 R132H and R132C mutants in vitro (IC50s = 0.07 and 0.16 µM, respectively) but not wild-type IDH1, wild-type IDH2, or IDH2 mutants (IC50s > 100 μM); anti-tumor efficacy in vitro and in vivo; induces demethylation of histone H3K9me3 and expression of genes associated with gliogenic differentiation.