OUTLINE: This is a dose-escalation, multicenter study. Patients are stratified according to study phase (I vs II), concurrent enzyme-inducing antiepileptic drugs (EIAEDs) (yes vs no), histology (recurrent GBM vs recurrent anaplastic glioma vs recurrent meningioma vs stable GBM), preoperative candidacy (yes vs no), and concurrent steroids (yes vs no).