In tumors from people diagnosed with
glioma, acute myeloid leukemia (AML), cholangiocarcinoma, and
chondrosarcoma, somatic mutations in the conserved active site of isocitrate dehydrogenase (IDH) 1 and 2 are observed. With these new mutations, these enzymes exhibit new, neomorphic behavior, which results in the reduction of α-ketoglutarate to the oncometabolite R-2-hydroxyglutarate. The new molecule competitively inhibits α-ketoglutarate–dependent enzymes, ultimately leading to epigenetic alterations and impaired hematopoietic differentiation. Mutations in the IDH1 enzyme mutations occur in approximately 6 to 10% of the patients with AML, and IDH2 mutations occur in approximately 9 to 13% of those with AML, with unknown statistics on other conditions listed. The drug is also believed to be a slow-binding inhibitor of the IDH1-WT homodimer. Ivosidenib showed
uncompetitive inhibition to the
NADP cofactor, showing a hyperbolic curve for the rate constant of inhibition relative to concentration. Ivosidenib also showed no time-dependence in
IC50 between 1 and 16 hours of incubation for either
homodimer. == References ==