title: DOT1L inhibitor EPZ-5676 displays synergistic antiproliferative activity in combination with standard of care drugs and hypomethylating agents in MLL-rearranged leukemia cells.
abstract: EPZ-5676 [(2R,3R,4S,5R)-2-(6-amino-9H-purin-9-yl)-5-((((1r,3S)-3-(2-(5-(tert-butyl)-1H-benzo[d]imidazol-2-yl)ethyl)cyclobutyl)(isopropyl)amino)methyl)tetrahydrofuran-3,4-diol], a small-molecule inhibitor of the protein methyltransferase DOT1L, is currently under clinical investigation for acute leukemias bearing MLL-rearrangements (MLL-r). In this study, we evaluated EPZ-5676 in combination with standard of care (SOC) agents for acute leukemias as well as other chromatin-modifying drugs in cellular assays with three human acute leukemia cell lines: MOLM-13 (MLL-AF9), MV4-11 (MLL-AF4), and SKM-1 (non-MLL-r). Studies were performed to evaluate the antiproliferative effects of EPZ-5676 combinations in a cotreatment model in which the second agent was added simultaneously with EPZ-5676 at the beginning of the assay, or in a pretreatment model in which cells were incubated for several days in the presence of EPZ-5676 prior to the addition of the second agent. EPZ-5676 was found to act synergistically with the acute myeloid leukemia (AML) SOC agents cytarabine or daunorubicin in MOLM-13 and MV4-11 MLL-r cell lines. EPZ-5676 is selective for MLL-r cell lines as demonstrated by its lack of effect either alone or in combination in the nonrearranged SKM-1 cell line. In MLL-r cells, the combination benefit was observed even when EPZ-5676 was washed out prior to the addition of the chemotherapeutic agents, suggesting that EPZ-5676 sets up a durable, altered chromatin state that enhances the chemotherapeutic effects. Our evaluation of EPZ-5676 in conjunction with other chromatin-modifying drugs also revealed a consistent combination benefit, including synergy with DNA hypomethylating agents. These results indicate that EPZ-5676 is highly efficacious as a single agent and synergistically acts with other chemotherapeutics, including AML SOC drugs and DNA hypomethylating agents in MLL-r cells.
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts.
authors.forename: Christine R
authors.initials: CR
authors.lastname: Klaus
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts.
authors.forename: Dorothy
authors.initials: D
authors.lastname: Iwanowicz
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts.
authors.forename: Danielle
authors.initials: D
authors.lastname: Johnston
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts.
authors.forename: Carly A
authors.initials: CA
authors.lastname: Campbell
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts.
authors.forename: Jesse J
authors.initials: JJ
authors.lastname: Smith
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts.
authors.forename: Mikel P
authors.initials: MP
authors.lastname: Moyer
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Copeland
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Olhava
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts.
authors.forename: Margaret Porter
authors.initials: MP
authors.lastname: Scott
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts.
authors.forename: Roy M
authors.initials: RM
authors.lastname: Pollock
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts.
authors.forename: Scott R
authors.initials: SR
authors.lastname: Daigle
authors.affiliation: Epizyme Inc., Cambridge, Massachusetts araimondi@epizyme.com.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Raimondi
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage*; D001562:Benzimidazoles / Q000008:administration & dosage*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D004357:Drug Synergism; D006131:Growth Inhibitors / Q000008:administration & dosage*; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy* / Q000473:pathology; D008745:Methylation / Q000187:drug effects; D008780:Methyltransferases / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D001562:Benzimidazoles; C583893:EPZ-5676; D006131:Growth Inhibitors; C473477:DOT1L protein, human; D008780:Methyltransferases; D011495:Histone-Lysine N-Methyltransferase