Epizyme, Inc. is a clinical-stage biopharmaceutical company. The Company discovers, develops and plans to commercialize epigenetic therapies for cancer patients. The Company's segment is the discovery and development of novel epigenetic therapies for cancer patients. It develops small molecule inhibitors of a class of enzymes known as histone methyltransferases, or HMTs. It develops small molecule inhibitors of other chromatin modifying proteins, or CMPs. Its lead product candidate, tazemetostat, is a selective inhibitor of the EZH2 HMT. It is evaluating tazemetostat in a Phase II study in adults with relapsed or refractory non-Hodgkin lymphoma, or NHL, and one Phase II study in adults and one Phase I study in children with certain genetically-defined solid tumors. It has programs in development, including a Phase I clinical trial of pinometostat, an inhibitor of the DOT1L HMT, for the treatment of children with MLL-r, an acute leukemia with genetic alterations of the MLL gene.