Tazemetostat in Treating Patients With Relapsed or Refractory Advanced Solid Tumors, Non-Hodgkin Lymphoma, or Histiocytic Disorders With EZH2, SMARCB1, or SMARCA4 Gene Mutations (A Pediatric MATCH Treatment Trial)

Inclusion Criteria

• Patient must have enrolled onto APEC1621SC and must have been given a treatment assignment to Molecular Analysis for Therapy Choice (MATCH) to APEC1621C based on the presence of an actionable mutation
• Patients must have radiographically measurable disease at the time of study enrollment; patients with neuroblastoma who do not have measurable disease but have MIBG+ evaluable disease are eligible; measurable disease in patients with CNS involvement is defined as tumor that is measurable in two perpendicular diameters on magnetic resonance imaging (MRI) and visible on more than one slice; Note: The following do not qualify as measurable disease:
• Malignant fluid collections (e.g., ascites, pleural effusions)
• Bone marrow infiltration except that detected by MIBG scan for neuroblastoma
• Lesions only detected by nuclear medicine studies (e.g., bone, gallium or positron emission tomography [PET] scans) except as noted for neuroblastoma
• Elevated tumor markers in plasma or cerebrospinal fluid (CSF)
• Previously radiated lesions that have not demonstrated clear progression post radiation
• Leptomeningeal lesions that do not meet the measurement requirements for Response Evaluation Criteria in Solid Tumors (RECIST) 1.1
• Karnofsky >= 50% for patients > 16 years of age and Lansky >= 50 for patients = = 21 days after the last dose of cytotoxic or myelosuppressive chemotherapy (42 days if prior nitrosourea)
• Anti-cancer agents not known to be myelosuppressive (e.g. not associated with reduced platelet or absolute neutrophil count [ANC] counts): >= 7 days after the last dose of agent
• Antibodies: >= 21 days must have elapsed from infusion of last dose of antibody, and toxicity related to prior antibody therapy must be recovered to grade = = 14 days must have elapsed since last dose of corticosteroid
• Hematopoietic growth factors: >= 14 days after the last dose of a long-acting growth factor (e.g. pegfilgrastim) or 7 days for short-acting growth factor; for growth factors that have known adverse events occurring beyond 7 days after administration, this period must be extended beyond the time during which adverse events are known to occur; the duration of this interval must be discussed with the study chair and the study-assigned research coordinator
• Interleukins, interferons and cytokines (other than hematopoietic growth factors): >= 21 days after the completion of interleukins, interferon or cytokines (other than hematopoietic growth factors)
• Stem cell Infusions (with or without total body irradiation [TBI]):
• Allogeneic (non-autologous) bone marrow or stem cell transplant, or any stem cell infusion including donor lymphocyte infusion (DLI) or boost infusion: >= 84 days after infusion and no evidence of graft versus host disease (GVHD)
• Autologous stem cell infusion including boost infusion: >= 42 days
• Cellular therapy: >= 42 days after the completion of any type of cellular therapy (e.g. modified T cells, natural killer [NK] cells, dendritic cells, etc.)
• Radiation therapy (XRT)/external beam irradiation including protons: >= 14 days after local XRT; >= 150 days after TBI, craniospinal XRT or if radiation to >= 50% of the pelvis; >= 42 days if other substantial bone marrow (BM) radiation; Note: Radiation may not be delivered to "measurable disease" tumor site(s) being used to follow response to subprotocol treatment
• Radiopharmaceutical therapy (e.g., radiolabeled antibody, 131I-MIBG): >= 42 days after systemically administered radiopharmaceutical therapy
• Patients must not have had prior exposure to tazemetostat or other inhibitor(s) of EZH2
• For patients with solid tumors without known bone marrow involvement:
• Peripheral absolute neutrophil count (ANC) >= 1000/mm^3
• Platelet count >= 100, 000/mm^3 (transfusion independent, defined as not receiving platelet transfusions for at least 7 days prior to enrollment)
• Hemoglobin >= 8.0 g/dL at baseline (may receive red blood cell [RBC] transfusi