CAMBRIDGE, Mass.--(BUSINESS WIRE)--Epizyme, Inc., a company leading the creation of a new class of personalized therapeutics for patients with genetically defined cancers, announced today that it has initiated a Phase 1 Study of EPZ-5676. EPZ-5676 is a novel small molecule inhibitor of DOT1L, a histone methyltransferase (HMT) that is critical to the development of a specific type of acute leukemia defined by rearrangement of the MLL gene (MLL-r leukemia). The Phase 1 study will evaluate the safety, pharmacokinetics, and pharmacodynamics of escalating doses of EPZ-5676 and will also provide a preliminary assessment of efficacy in a cohort of patients with MLL-r leukemia. Epizyme anticipates that approximately 40 patients will be accrued to this Phase 1 study.