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.