Safusidenib is a selective, orally active mutant inhibitor of IDH1 that significantly inhibits mutant IDH1, but not wild-type IDH1, and inhibits tumor activity in chondrosarcoma. safusidenib is active against IDH1R132H and IDH1R132C, and in the absence of preincubation, the IC50 values were 15 and 130 nM, respectively.