This 2 arm study investigated the efficacy and safety of the addition of bevacizumab 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. Participants were randomly assigned to either the bevacizumab (10 milligrams per kilogram (mg/kg) intravenously [IV] once every 2 week [q2w]) or the placebo arm, in combination with radiation therapy (total dose 60 Gray [Gy], administered as 2 Gy fractions, 5 days/week) plus temozolomide (75 milligrams per meter squared [mg/m^2] oral administration [po] daily) for 6 weeks. After a 4 week treatment break, participants continued to receive bevacizumab (10 mg/kg IV q2w) or placebo, plus temozolomide (150-200 mg/m^2 po daily on days 1-5 of each 4 week cycle) for 6 cycles of maintenance treatment or until disease progression or unacceptable toxicity, whichever occured first. Following the maintenance phase, bevacizumab (15 mg/kg iv every 3 weeks [q3w]) or placebo monotherapy continued. The time on study treatment was until disease progression.