Bevacizumab, Temozolomide, and External Beam Radiation Therapy as First-Line Therapy in Treating Patients With Newly Diagnosed Glioblastoma Multiforme or Gliosarcoma

OBJECTIVES: Primary * To investigate the safety and tolerability of bevacizumab in combination with temozolomide and external beam fractionated regional radiotherapy as first-line treatment in patients with newly diagnosed glioblastoma multiforme or gliosarcoma. (Pilot phase) * To estimate the overall survival of patients treated with this regimen. (Expansion phase) Secondary * To further investigate the safety and tolerability of this regimen in these patients. (Expansion phase) * To isolate DNA, RNA, and protein from frozen and paraffin-embedded archival tumor samples for evaluations, such as immunohistochemical pathway profiling of vascular endothelial growth factor (VEGF)-dependent angiogenic pathways, gene expression microarray, and O-6 methylguanine DNA methyltransferase (MGMT) promoter methylation status to define important molecular features of treatment response. OUTLINE: This is a multicenter study. Patients undergo external beam fractionated regional radiotherapy once daily 5 days a week for 6 weeks and receive concurrent oral temozolomide once daily for 6 weeks. Patients also receive bevacizumab IV over 30-90 minutes every 2 weeks beginning on the first day of radiotherapy and continuing in the absence of disease progression or unacceptable toxicity. Beginning 2-5 weeks after completion of radiotherapy, patients receive oral temozolomide on days 1-5. Treatment with temozolomide repeats every 28 days for up to 24 courses in the absence of disease progression or unacceptable toxicity. Blood and frozen and paraffin-embedded tumor tissue samples are collected for biomarker and genetic analysis. After completion of study treatment, patients are followed up periodically.