Combination targeted therapy to disrupt aberrant oncogenic signaling and reverse epigenetic dysfunction in IDH2- and TET2-mutant acute myeloid leukemia (RNA-Seq)

Genomic studies in acute myeloid leukemias (AML) have identified mutations which drive altered DNA methylation, including TET2 and IDH. Functional studies have shown these mutations contribute to transformation, although how these mutations impact the response to epigenetic therapies is not fully delineated. Here we show AMLs with TET2/IDH2 mutations combined with FLT3ITD mutations are specifically sensitive to 5-Azacytidine or to the IDH2 inhibitor AG-221, respectively. 5-Azacytidine/AG-221 therapies induced a reduction in leukemic blasts and in stem/progenitor expansion, with attenuation of aberrant DNA hypermethylation. These therapeutic benefits were achieved through restoration of differentiation, such that normalized hematopoiesis was derived from mutant cells. Consistent with these data, at the time of clinical response to 5-Azacytidine or AG-221, most patients had mutant-derived hematopoiesis. By contrast, combined AG-221/5-Azacytidine plus FLT3 inhibition reduced disease burden and reversed epigenetic dysfunction. Our studies suggest combined targeting of signaling and epigenetic pathways can increase therapeutic response in AML. Overall design: We profiled genome-wide transcription patterns of the hematopoietic stem cells (LSK) population in Wild-type, Idh2 R140Q Flt3-ITD, and Tet2-/-;Flt3-IDT mice. Idh2 R140Q Flt3-ITD mice with AML were treated with either vehicle or AG-221 (the first small molecule in vivo inhibitor of IDH2 to enter clinical trials). Tet2-/-;Flt3-IDT mice with AML were treated with vehicle or 5-Azacytidine (Decitabine, hypomethylating agent).

19

Shih AH, Meydan C, Shank K, Garrett-Bakelman FE, Ward PS, Intlekofer AM, Nazir A, Stein EM, Knapp K, Glass J, Travins J, Straley K, Gliser C, Mason CE, Yen K, Thompson CB, Melnick A, Levine RL