Avastin/Radiation (XRT)/Temozolomide (Temodar) Followed by Avastin/Temodar/Topotecan for Glioblastoma

Inclusion Criteria: * Patients must have histologically confirmed diagnosis of WHO grade IV primary malignant glioma (glioblastoma multiforme or gliosarcoma). Patients have to be within 6 weeks of the last major surgical procedure. * Age \> or = to 18 years. * An interval of at least 2 weeks and not \> 6 weeks between prior major surgical procedure and study enrollment. * No prior radiotherapy or chemotherapy for a brain tumor * Karnofsky \> or = to 60%. * Hemoglobin ≥ 9.0 g/dl, absolute neutrophil count (ANC) ≥ 1,500 cells/microliter, platelets ≥ 125,000 cells/microliter. * Serum creatinine ≤ 1.5 mg/dl, serum glutamic oxaloacetic transaminase (SGOT) and bilirubin ≤ 1.5 times upper limit of normal. * Signed informed consent approved by the Institutional Review Board * If sexually active, patients must agree to use appropriate contraceptive measures for the duration of the study and for 6 months afterwards as stated in the informed consent. Exclusion Criteria: * Pregnancy or breast feeding. * Co-medication that may interfere with study results; e.g. immuno-suppressive agents other than corticosteroids. * Active infection requiring IV antibiotics. * Prior treatment with radiotherapy or chemotherapy for a brain tumor, irrespective of the grade of the tumor. * Evidence of \> grade 1 central nervous system (CNS) hemorrhage on baseline MRI on CT scan. Avastin-specific Exclusion Criteria: * Inadequately controlled hypertension (defined as systolic blood pressure \> 150 and/or diastolic blood pressure \> 100 mmHg) * Prior history of hypertensive crisis or hypertensive encephalopathy * New York Heart Association (NYHA) Grade II or greater congestive heart failure * History of myocardial infarction or unstable angina within 6 months prior to study enrollment * History of stroke or transient ischemic attack within 6 months prior to study enrollment * Significant vascular disease (e.g., aortic aneurysm, requiring surgical repair or recent peripheral arterial thrombosis) within 6 months prior to study enrollment * History of hemoptysis (≥ ½ teaspoon of bright red blood per episode) within 1 month prior to study enrollment * Evidence of bleeding diathesis or coagulopathy (in the absence of therapeutic anticoagulation) * Major surgical procedure, open biopsy, or significant traumatic injury within 28 days prior to study enrollment or anticipation of need for major surgical procedure during the course of the study * Core biopsy or other minor surgical procedure, excluding placement of a vascular access device, within 7 days prior to study enrollment * History of abdominal fistula, gastrointestinal perforation within 6 months prior to study enrollment * Serious, non-healing wound, active ulcer, or untreated bone fracture * Proteinuria at screening as demonstrated by either urine protein:creatinine (UPC) ratio ≥ 1.0 at screening OR urine dipstick for proteinuria ≥ 2+ (patients discovered to have ≥2+ proteinuria on dipstick urinalysis at baseline should undergo a 24-hour urine collection and must demonstrate ≤ 1g of protein in 24 hours to be eligible). * Known hypersensitivity to any component of Avastin * Pregnant (positive pregnancy test) or lactation. Use of effective means of contraception (men and women) in subjects of child-bearing potential