STEP I: Patients must not have active, uncontrolled seizure disorder; patients must have had no seizures in the last 6 months Patients with uncontrolled seizure disorder are not eligible; (patients with seizure disorders that do not require antiepileptic drugs, or are well controlled with stable doses of antiepileptic drugs remain eligible) Patients with active seizures or a history of uncontrolled seizure disorder, including focal or generalized seizure within the past year Patients with a history of seizure disorder requiring antiepileptic medication or brain metastases with seizures are NOT eligible for participation History of seizures, prior traumatic brain injury, prior stroke, or other predisposing risk of seizure (excluding CNS metastasis) History of seizure disorder requiring antiepileptic medication or brain metastases with seizures Seizures disorder not controlled by anti-seizure medications Any chronic or active neurologic disorder, including seizures and epilepsy, excluding a single febrile seizure as a child Any history of epilepsy or a seizure disorder or any known prior seizures. Any chronic or active neurologic disorder, including seizures and epilepsy, excluding a single febrile seizure as a child Adequate central nervous system function defined as:\r\n* Subjects with seizure disorder may be enrolled if on anticonvulsants and seizures are well controlled Patients with a history of active seizures (or a single confirmed seizure event) in the last 2 years from the time of registration Uncontrolled seizure disorder (ie, seizures within the past 2 months). Uncontrolled seizure disorder (ie, seizures within the past 2 months). For subjects with ATRT only, subject must have seizures that are stable, not increasing in frequency or severity and controlled on current anti-seizure medication(s) for a minimum of 21 days prior to the planned first dose of tazemetostat Any chronic or active neurologic disorder, including seizures and epilepsy, excluding a single febrile seizure as a child Any chronic or active neurologic disorder, including seizures and epilepsy, excluding a single febrile seizure as a child Patients with a seizure disorder are study eligible if seizures are controlled on anticonvulsants Patients with a history of uncontrolled seizures or who are not on anti seizure medication (e.g., Phenytoin 100 mg PO t.i.d. or Keppra 500 mg po bid) before the procedure Patients with seizure disorder may be enrolled if seizures are well-controlled (i.e., patients must not have required rescue medications for uncontrolled seizures within 14 days prior to enrollment) Patients with uncontrolled seizures or seizure requiring escalation or addition of anti-epileptic drugs will be excluded Patients with a history of seizure disorder (except infant febrile seizures) Patients with seizure disorder may be enrolled if on anticonvulsants and if seizures are well controlled Patients with a high risk of seizures should be excluded from the protocol (e.g. those patients with an uncontrolled seizure disorder, and/or patients who have had a focal or generalized seizure within the last 12 months) Patients with a history of encephalitis, multiple sclerosis, or seizures within the last year (from seizure disorder or brain metastasis) should be excluded from this clinical trial History of seizure disorder requiring antiepileptic medication or brain metastases with seizures Patients must not have active, uncontrolled seizure disorder; patients must have had no seizures in the last 6 months Comorbid conditions: patients are unable to participate due to the following:\r\n* Generalized or partial seizure disorder that is uncontrolled at the time of registration; the definition of controlled generalized seizures is patients must be on a stable dose of anti-seizure medication and without generalized seizures for at least 10 days prior to registration; the definition of controlled partial seizures is patients must be on a stable dose of anti-seizure medication for at least 10 days prior to registration; patients with occasional breakthrough partial seizures are allowed at treating physician’s discretion\r\n* Grade 3 or 4 thromboembolic disease within 6 months (mo) of registration\r\n* Known history of prolonged QT syndrome Patients with epilepsy, seizures, or predisposing factors for seizure as judged by the investigator. History of seizure any time in the past for any reason or any condition that may predispose to seizures. Patients with seizure disorder may be enrolled if seizures are well controlled Any history of seizures or medical condition which lowers seizure threshold Patients with a prior seizure disorder requiring anti-convulsant therapy are not eligible to receive nelarabine. For the purposes of this study, this includes any patient that has received anticonvulsant therapy to prevent/treat seizures in the prior two years. Subjects with seizure disorder may be enrolled if on anticonvulsants and seizures are well controlled History of seizures (unless seizure free for 5 years); Patients with active seizures or a history of seizure are not eligible for study entry, with the exception of patients with documented febrile seizure Intractable seizures while on adequate anticonvulsant therapy—more than 1 seizure per week for the past 2 months Intractable seizures while on adequate anticonvulsant therapy—more than 1 seizure per month for the past 2 months Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and well controlled Patients must not have received enzyme-inducing anticonvulsants for at least 7 days prior to enrollment Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and well controlled Patients must not have received enzyme inducing anticonvulsants for at least 14 days prior to enrollment Patients with seizure disorder may be enrolled if on non-enzyme inducing anti-convulsants and well controlled Patients must not have received enzyme-inducing anticonvulsants for at least 7 days prior to enrollment Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled; however, drugs that induce CYP3A4/5 (carbamazepine, oxcarbazepine, phenytoin, primidone, phenobarbital) should be avoided Central nervous system function defined as:\r\n* Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled\r\n* Patients must not be in status epilepticus, a coma or on assisted ventilation at the time of study enrollment Patients with a known seizure disorder who are receiving non-enzyme inducing anticonvulsants and have well-controlled seizures may be enrolled Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled Concomitant use of any enzyme inducing anticonvulsants is not allowed Subjects who are currently receiving enzyme inducing anticonvulsants are not eligible Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and well controlled Patients must not currently be receiving enzyme inducing anticonvulsants Patients receiving concomitant medication that may interfere with study outcome; for example, patients cannot be on enzyme inducing anticonvulsants like phenytoin Patients receiving treatment with any enzyme-inducing anticonvulsant that cannot be discontinued at least 1 week before first dose of INC280, and for the duration of the study; patients on non-enzyme-inducing anticonvulsants are eligible Patients with seizure disorder may be enrolled if receiving non-enzyme inducing anticonvulsants and well controlled Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and well controlled. Patients with known seizure disorder must have seizures adequately controlled with non- enzyme inducing antiepileptic medications Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and well controlled Patients with seizure disorder may be enrolled if receiving non-enzyme inducing anticonvulsants and well controlled Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and well controlled Patients who are currently receiving enzyme inducing anticonvulsants are not eligible Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and well controlled Anticonvulsants: patients on enzyme inducing anticonvulsants (EIAED) will be excluded; if patients were previously on EIAEDs that have been discontinued, patients must have been off EIAEDs for >= 2 weeks prior to initiation of dasatinib Patients with a seizure disorder may be enrolled if well-controlled and on non-enzyme inducing anticonvulsants Patients with seizure disorder may be enrolled if well controlled; patients receiving enzyme-inducing anticonvulsants are not eligible for this study; patients must be off enzyme inducing anticonvulsant drugs (EIACD) for at least 2 weeks prior to registration Patients on enzyme inducing anticonvulsants Concomitant use of any enzyme inducing anticonvulsants is not allowed Subjects with seizure disorder may be enrolled if on anticonvulsants and well controlled Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled Treatment with non-enzyme inducing anti-seizure medications is allowed Central nervous system function defined as:\r\n* Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled\r\n* Patients must not be in status, coma or assisted ventilation prior to study enrollment Brain metastases that are symptomatic or requiring corticosteroids (except inhaled); subjects must also be off of enzyme-inducing anticonvulsants for > 4 weeks Central nervous system function defined as\r\n* Patients with a seizure disorder may be enrolled if well-controlled and on non-enzyme inducing anticonvulsants Patients must not have received enzyme-inducing anticonvulsants including phenytoin, phenobarbital, valproic acid, or carbamazepine for at least 7 days prior to study enrollment; patients receiving non-enzyme inducing anticonvulsants such as gabapentin or levetiracetam will be eligible Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and if seizures are well controlled Patients who are currently receiving enzyme inducing anticonvulsants are not eligible Patients with known seizure disorder must have seizures adequately controlled with non-enzyme inducing antiepileptic medications Participants who are currently receiving enzyme-inducing anticonvulsants Patients with seizure disorder may be enrolled if on anticonvulsants and well controlled Patients taking enzyme inducing anticonvulsants Use of enzyme-inducing anticonvulsants (EIACs); a minimum interval of 10 days between the last dose of EIAC and start of this therapy will be required for research participants who were previously receiving such medications Central nervous system function defined as:\r\n* Patients with seizure disorder may be enrolled if on non-enzyme inducing anticonvulsants and if seizures are well controlled\r\n* Nervous system disorders (Common Terminology Criteria for Adverse Events [CTCAE] version 4 [v4]) resulting from prior therapy must be =< grade 2 Patients who are currently receiving enzyme inducing anticonvulsants are not eligible No enzyme inducing anticonvulsants for >= 4 weeks prior to randomization Patients can only be on non-enzyme inducing anti-convulsants; if they are on an enzyme inducing anti-convulsant, they may be converted to a non-enzyme inducing anticonvulsants Central Nervous System: Patients without seizure disorder OR patients with well-controlled seizure disorder receiving anticonvulsants may be enrolled on this protocol; anticonvulsants must not be enzyme-inducing (inducers of CYP3A, i.e., no barbiturates, phenytoin, carbamazepine, etc.) Patients with seizure disorder may be enrolled if on anticonvulsants and well-controlled; central nervous system (CNS) toxicity < grade 2 Patients must not have received enzyme inducing anticonvulsants for at least 14 days prior to enrollment Patients with a seizure disorder are eligible if well-controlled on anticonvulsants; if on a non-enzyme inducing anticonvulsant, the irinotecan (irinotecan hydrochloride) dose will be adjusted as outline in treatment plan Patients with brain metastases are eligible provided they meet all other eligibility criteria and do not require corticosteroids or enzyme-inducing anticonvulsants and provided it is felt clinically that they will not require radiotherapy in the three (3) weeks subsequent to their participation in the study Patients with seizure disorder may be enrolled if on anti-convulsants and well controlled History of seizure disorder or active use of anticonvulsants History of uncontrolled seizure disorder Current or history of seizure disorder Patients with seizure disorder requiring medication Patients who have an uncontrolled seizure disorder, or active neurological disease Subjects with a seizure disorder that is not well controlled or who have required a change in seizure medications within 60 days of enrollment to the trial. History of seizure disorder. history of seizure disorder Patients with a seizure disorder should be well controlled Patients with seizure disorder may be enrolled if seizure disorder is well controlled Patients with seizure disorder requiring medication Patients with seizure disorder requiring medication Patients with seizure disorder requiring medication Patients who have a history of a seizure disorder requiring anti-seizure medication. History of seizure disorder not related to underlying cancer Serum albumin ? 2 g/dL. Neurologic Function: • Patients with seizure disorder may be enrolled if seizure disorder is well controlled. History of seizure disorder Diagnosis of seizure disorder Patients will not be eligible if they present or have a history of seizure disorder FOR ALL PHASES (Ib AND II): Patients with seizure disorder requiring medication Patients with seizure disorder requiring medication Seizure disorder requiring medication Patients with seizure disorder requiring medication Known seizure disorder Clinically evident CNS metastases or leptomeningeal disease not controlled by prior surgery or radiotherapy; history of seizure disorder not controlled by anti-seizure medication at the time of enrollment. Patients with primary CNS malignancies are excluded. Patients with seizure disorder requiring medication Seizure disorder requiring enzyme-inducing anti-epileptic drugs (EIAEDs)\r\n* Note: If the seizure disorder can be managed with agents that are not EIAEDs (e.g., levetiracetam or valproate), the patient should not be excluded REGORAFENIB EXCLUSION CRITERIA: Patients with seizure disorder requiring medication Patients with seizure disorder requiring medication Prior history of seizure disorder Seizure disorder requiring medication Documented uncontrolled seizure disorder– a seizure disorder controlled with medication (i.e. no seizures in the previous 6 months) will not exclude a patient Reports diagnosis of seizure disorder Clinically evident central nervous system metastases or leptomeningeal disease not controlled by prior surgery or radiotherapy; history of seizure disorder not controlled by anti-seizure medication at the time of enrollment. Patients with any seizure disorder Patients with any history of seizure or seizure disorder History of seizure disorder History of seizure disorder History of seizure disorder or clinically treated bipolar disorder Have a seizure disorder where > 1 seizure has occurred within the last year. Patients with seizure disorder requiring medication (such as steroid anti-epileptics) Patients with seizure disorder requiring medication Active seizure disorder uncontrolled by medication Patient has no known history of seizure disorder Uncontrolled seizure disorder Patients with seizure disorder may be enrolled if well controlled Active seizure or history of seizure disorder Patients with seizure disorder requiring medication Uncontrolled seizure disorder Patients with seizure disorder requiring medication Uncontrolled, active seizure disorder or a history of seizure History of uncontrolled severe seizure disorder History of uncontrolled severe seizure disorder Patients who have an uncontrolled seizure disorder, or active neurological disease Patients who have had a seizure within 12 months prior to enrollment and patients receiving anti-convulsant therapy for a seizure disorder. Patients with seizure disorder requiring medication. Uncontrolled seizure disorder, active neurological disease, or known CNS disease. Patients with seizure disorder requiring medication Patients with seizure disorder requiring medication. Uncontrolled seizure disorder Patients with seizure disorder requiring medication Patients with seizure disorder requiring medication Patients with seizure disorder requiring medication Patients with any seizure disorder requiring medication Patients with seizure disorder requiring medication Patients with seizure disorder requiring medication History of epilepsy or seizure disorder A history of uncontrolled seizure disorder Patients with seizure disorder requiring medication Seizure disorder Patients with seizure disorder may be enrolled if well controlled Active central nervous system (CNS) disorder or seizure disorder Uncontrolled seizure disorder or other serious neurological diseases Subjects with seizure disorder currently requiring medication. Past or current history of epilepsy or seizure disorder Have a seizure disorder requiring medication. History of seizure disorder Prior history of seizure disorder Uncontrolled seizure disorder or active neurologic disease Known brain metastases, uncontrolled seizure disorder, or active neurologic disease Known brain metastases, uncontrolled seizure disorder, or active neurologic disease Uncontrolled seizure disorder or active neurologic disease Uncontrolled seizure disorder or active neurologic disease Uncontrolled seizure disorder requiring therapy (such as steroids or anti-epileptics with significant CYP interaction) Seizure disorder requiring anticonvulsant therapy (such as steroids or anti-epileptics) Uncontrolled seizure disorder. History of seizure disorder not related to underlying cancer. Donor must have adequate neurologic function as defined by NO evidence of a severe central or peripheral neurologic abnormality and no history of cerebrovascular accident or seizure disorder requiring anticonvulsant medication. Uncontrolled seizure disorder, active neurological disease, or greater than Grade 2 neuropathy. Patients with seizure disorder requiring medication History of intractable epilepsy, or uncontrolled seizure disorder History of seizure disorder Uncontrolled seizure disorder Patients with seizure disorder requiring medication History of a seizure disorder or requirement for anti-seizure medication Uncontrolled seizure disorder Participant has uncontrolled seizure disorder in past 12 months Patient must not have a seizure disorder Subjects with a history of seizure disorder taking anti-seizure medication within 30 days prior to randomization. Seizure disorder Known history of epilepsy/seizure disorder History of epileptic disorder or any seizure history unrelated to tumor Huntington’s disease, hydrocephalus or seizure disorder Seizure disorder