LY3410738, a Covalent Inhibitor of Mutant IDH1/2, is Effective in Acute Myeloid Leukemia Preclinical Models

Acute myeloid leukemia (AML) is an aggressive blood disorder characterized by rapid growth of poorly differentiated myeloid cells. Gain-of-function mutations in isocitrate dehydrogenases (IDHs) are detected in ~20% of AML and ~80% of secondary gliomas. Mutant IDH1/2 isoenzymes acquire neomorphic activity to produce 2-hydroxyglutarate (2-HG) oncometabolite, resulting in hypermethylated DNA and histones, altered gene expression, and blocked differentiation of hematopoietic progenitors. Here, we presented preclinical development of LY3410738, an oral, dual IDH1/2 inhibitor with potential to penetrate the blood-brain barrier. LY3410738 covalently inhibited mutated-IDH1/2, reduced 2-HG levels at low nanomolar concentrations in human AML and glioma models, and demonstrated efficacy in AML patient-derived xenografts (PDXs) in vivo, inducing myeloid differentiation. LY3410738 retained in vitro activity in cancer models with acquired secondary IDH1/2 mutations conferring resistance to ivosidenib and enasidenib. LY3410738 synergized and was well tolerated with standard-of-care regimens such as cytarabine, azacitidine, venetoclax, or midostaurin in IDH1/2-mutated AML PDXs.