This 2 arm study will investigate the efficacy and safety of the addition of bevacizumab (Avastin) to the current standard of care (multimodality therapy of concurrent radiotherapy plus temozolomide followed by adjuvant temozolomide) as compared to the current standard of care alone. Patients will be randomly assigned to either the Avastin (10mg/kg iv q2w)or the placebo arm, in combination with radiation therapy (total dose 60 Gy, administered as 2 Gy fractions, 5 days/week)plus temozolomide (75mg/m2po daily) for 6 weeks.After a 4 week treatment break,patients will continue to receive Avastin (10mg/kg iv q2w) or placebo, plus temozolomide (150-200mg/m2 po daily on days 1-5 of each 4 week cycle) for 6 cycles of maintenance treatment. Following the maintenance phase,Avastin (15mg/kg iv q3w) or placebo monotherapy will continue. The anticipated time on study treatment is until disease progression, and the target sample size is 500+ individuals.

• Drug: bevacizumab [Avastin]
  10mg/kg iv q2w
• Drug: Placebo
  iv q2w
• Drug: temozolomide
  75mg/m2 po once daily for 6 weeks, followed by 150-200mg/m2 po daily on days 1-5 of each 6 x 4 week cycle
• Radiation: Radiation therapy
  30 fractions of 2 Gy delivered on days 1-5 per week for 6 weeks

• 1: Experimental
  Interventions:

  • Drug: bevacizumab [Avastin]
  • Drug: temozolomide
  • Radiation: Radiation therapy
• 2: Placebo Comparator
  Interventions:

  • Drug: Placebo
  • Drug: temozolomide
  • Radiation: Radiation therapy

Inclusion Criteria:

• adult patients, >=18 years of age;
• newly diagnosed glioblastoma;
• WHO performance status <=2;
• stable or decreasing corticosteroid dose within 5 days prior to randomization.

Exclusion Criteria:

• evidence of recent hemorrhage or postoperative MRI of brain;
• any prior chemotherapy or immunotherapy for glioblastomas and low grade astrocytomas;
• any prior radiotherapy to brain;
• clinically significant cardiovascular disease;
• history of >=grade 2 hemoptysis within 1 month prior to randomization;
• previous centralized screening for MGMT status for enrollment into a clinical trial.