HUMC 1612: Optune NovoTTF-200A System

Inclusion Criteria: * Patients must have a minimum head circumference of 44 cm * Patients must have a histologically- or cytologically-confirmed supratentorial high-grade glioma or supratentorial ependemoma. * Patients with metastatic disease involving the infratentorium or spinal cord are eligible providing that they have a supratentorial tumor that is able to be targeted with TTFields. * Eligible pathologic diagnoses include: High-grade Glioma (WHO Grade III or IV): Anaplastic Astrocytoma, Astroblastoma, Diffuse Midline Glioma, Glioblastoma, Gliosarcoma Ependymoma (WHO Grade II or III):Ependymoma, Anaplastic Ependymoma * Patients with high-grade glioma must must have be newly-diagnosed or have a tumor that is progressive or recurrent following standard treatment. Patients with ependymoma must have a tumor that is progressive or recurrent following standard treatment. * Patients must have received the maximal feasible resection of their tumor and radiation therapy (unless contraindicated due to patient age) as part of their initial treatment prior to study enrollment. * Patients must be enrolled before treatment begins. Treatment must start within 14 days of study enrollment. * All clinical and laboratory studies to determine eligibility must be performed within 7 days prior to enrollment unless otherwise indicated in the eligibility section. * Newly-diagnosed patients must begin therapy within six weeks of the completion of radiotherapy, or within six weeks of surgical resection if radiotherapy is contraindicated. * Recurrent high-grade glioma patients must begin therapy within four weeks of documented tumor progression by MRI scan. * Patients must have a Lansky or Karnofsky performance status score of ≥ 50%, corresponding to ECOG categories of 0, 1 or 2. Use Karnofsky for patients \> 16 years of age and Lansky for patients ≤ 16 years of age. Patients who are unable to walk because of paralysis, but who are up in a wheelchair will be considered ambulatory for the purpose of assessing the performance score. * Able to undergo adequate tumor imaging, via magnetic resonance imaging (MRI) scan to evaluate disease evolution. * Adequate hematologic, renal, liver function as demonstrated by laboratory values: ANC ≥ 1,000/ul Hemoglobin ≥8.0 gm/dl Platelet count ≥ 100,000/ul Adequate Liver Function Defined As: * Total bilirubin ≤ 1.5 x upper limit of normal (ULN) for age, and * SGPT (ALT) \< 2.5 x upper limit of normal (ULN) for age. Adequate Renal Function Defined As Either * Creatinine clearance or radioisotope GFR ≥ 70ml/min/1.73m2 * or a serum creatinine less than or equal to the institutional normal for age * Negative pregnancy test in women of childbearing potential within 7 days of initiating investigational therapy * Recent mothers must agree not to breast feed while receiving medications on study * Patient or legal guardian must give written, informed consent or assent (when applicable). * Able to swallow and ingest oral medication or have a NG or G-tube for drug administration * Urine protein should be screened by urine analysis. If protein ≥ 2+ on urinalysis, then Urine Protein Creatinine (UPC) ratio should be calculated. If UPC ratio \> 0.5, 24-hour urine protein should be obtained and the level should be \< 1000 mg for patient enrollment. Note: UPC ratio of spot urine is an estimation of the 24 urine protein excretion - a UPC ratio of 1 is roughly equivalent to a 24-hour urine protein of 1000 mg. UPC ratio is calculated using one of the following formula: * \[urine protein\]/\[urine creatinine\] - if both protein and creatinine are reported in mg/dL * \[(urine protein) x0.088\]/\[urine creatinine\] - if urine creatinine is reported in mmol/L * Adequate Coagulation Defined As: PT/INR ≤ 1.5 x upper limit of normal Exclusion Criteria: * Age less than 5 or greater than or equal to 18 years * Head circumference \< 44 cm * Absence of supratentorial tumor * Use of any other investigational drug within five half-lives of that drug prior to the initiation of protocol therapy * Anti-cancer therapy within 4 weeks prior to the initiation of protocol therapy (6 weeks for mitomycin and nitrosureas, 4 weeks for curative-intent radiotherapy, and 2 weeks for palliative radiotherapy) * Any National Cancer Institute (NCI) Common Toxicity Criteria for Adverse Events (CTCAE version 4.0) \>Grade 1 toxicities from prior chemotherapy or radiotherapy that could impact on safety outcome assessment * Any surgery within 14 days prior to initiation of protocol therapy (excluding shunt or line insertion) * Implanted pacemaker, programmable shunts, defibrillator, deep brain stimulator, other implanted electronic devices in the brain, or documented clinically significant arrhythmias. * Evidence of increased intracranial pressure (midline shift \> 5mm, clinically significant papilledema, vomiting and nausea or reduced level of consciousness) Patients receiving escalating doses of corticosteroids to control symptoms of increased intracranial pressure (e.g., require a stable or decreasing dose of corticosteroids for at least 7 days prior to enrollment) will also be excluded. * Known \> Grade 1 intracranial or intratumoral hemorrhage either by CT or MRI scan within the last 1 month. Patients with resolving hemorrhage changes, punctuate hemorrhage or hemosiderin may enter the study * Pregnant female patients, Pregnancy tests with a negative result must be obtained in all post-menarchal females. * Lactating females must agree they will not breastfeed a child while on this study. * Males and females of reproductive potential may not participate unless they agree to use an effective contraceptive method and continue to do so for at least 6 months after the completion of therapy. * Any serious and/or unstable pre-existing medical, psychiatric or other condition which in the Investigator's opinion could interfere with subject safety, obtaining written informed consent, or compliance with the study protocol * Known hypersensitivity to temozolomide or bevacizumab * Patients who are unable to take oral medications because of significant uncontrolled vomiting will be excluded. * Patients must not have a history of myocardial infarction, severe or unstable angina, clinically significant peripheral vascular disease, Grade 2 or greater heart failure, or serious and inadequately controlled cardiac arrhythmia. * Patients must not have a known clinically significant bleeding diathesis or coagulopathy * Patients who have experienced arterial thromboembolic events, including transient ischemic attacks or cerebrovascular accidents are excluded from participation. * Patients must not have been previously diagnosed with a deep venous thrombosis (including pulmonary embolism), and must not have a known thrombophilic condition (e.g., protein S, protein C, antithrombin III deficiency, Factor V Leiden or Factor II G202'0A mutation, homocysteinemia, or antiphospholipid antibody syndrome). * Patients must not have a history of an abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within the last 6 months prior to study entry. * Patients with a serious or non-healing wound, ulcer, or bone fracture are not eligible for this study. * Patients with a history of allergic reaction to Chinese hamster ovary cell products, or other recombinant human antibodies are ineligible.