The investigators propose to conduct a multicenter, open-label, randomized, phase II study in patients with newly diagnosed glioblastoma (CeCil). Patients should meet all eligibility criteria for the CENTRIC phase III trial at the exception that no MGMT-promoter methylation could be demonstrated. The treatment backbone in both study arms will consist of postoperative radiation therapy with concomitant daily temozolomide, followed by 6 cycles of temozolomide according to a 21 out of 28 days regimen (as in the experimental arm of the RTOG 0525 / EORTC 26052-22053 phase III study). In study arm (A) Cilengitide (at a dose of 2000 mg by iv administration, 2x/week) will be added to this backbone while in the second study arm (B), Cetuximab will be added (at an initial dose of 400 mg/m² administered by intravenous infusion over 2 hours and followed by a weekly dose of 250 mg/m² iv over 1 hours). In both study arms, treatment will be administered for 52 consecutive treatment weeks. The 1-year overall survival (1y-OS) following randomization will serve as the primary endpoint in both study arms.