Inclusion Criteria:

• Histologic documentation: newly diagnosed World Health Organization (WHO) grade IV intracranial glioblastoma or gliosarcoma; GBM with oligodendroglial features are NOT PERMITTED in this study if they are 1p19q codeleted; sites submitting GBM with oligodendroglial features will be asked to provide results of 1p/19q codeletion status
• Sufficient tissue available for central pathology review and MGMT methylation status evaluation
• Patients who have had a local MGMT testing that is unmethylated are not allowed to participate
• Tumor MGMT promoter hypermethylation determined by central testing at MD Anderson
• Confirmation by central pathology review of WHO grade IV glioblastoma or gliosarcoma
• Absolute neutrophil count (ANC) ≥ 1500 cells/mm^3
• Platelets ≥ 100,000 cells/mm^3
• Creatinine ≤ 1.5 x upper limit of normal (ULN)
• Bilirubin ≤ 1.5 x ULN; unless patient has Gilbert's disease
• Alanine aminotransferase (ALT) ≤ 3 x ULN
• Aspartate aminotransferase (AST) ≤ 3 x ULN
• Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2
• Measurable disease or non-measurable disease; extent of resection: patients with complete resection, partial resection, or biopsy are eligible
• Progression: patients deemed to have progressive disease based on clinical deterioration after chemoradiation or radiographic progression outside of the radiation field are not eligible; patients deemed to have pseudoprogression are eligible
• Prior treatment:
  • Must have completed standard radiotherapy and concomitant TMZ therapy as defined and determined by the study oncologist
  • Besides concomitant TMZ with radiation, no other therapy (neo-adjuvant or adjuvant) can be given prior to study registration, including chemotherapy, biologics, immunotherapy, radiation therapy, or Novo-TTF-100A System
• Not pregnant and not nursing; females of childbearing potential must have negative urine or serum pregnancy test within 7 days of registration but before start of treatment; a female of childbearing potential is a sexually mature female who: 1) has not undergone a hysterectomy or bilateral oophorectomy; or 2) has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months)
• Concomitant medications: patients receiving anticoagulation should be on stable dose 2 weeks prior to registration
• Comorbid conditions: patients are unable to participate due to the following:
  • Seizure disorder that is uncontrolled at the time of registration; the definition of controlled seizures is patients must be without seizures for at least 10 days prior to registration
  • Grade 3 or 4 thromboembolic disease within 6 months (mo) of registration
  • Known history of prolonged QT syndrome
• No history of major surgery ≤ 14 days prior to registration