Study of IDO Inhibitor and Temozolomide for Adult Patients With Primary Malignant Brain Tumors

The aim of this study is to identify the safety profile and the recommended dose for phase 2 study of the combination of indoximod (portion 1, phase 1b study). Investigators will then evaluate the tolerability and the preliminary activity in patients with recurrent GBM in three different situations: * Combination of indoximod and temozolomide (bevacizumab-naive patients) * Combination of indoximod and temozolomide in patients currently receiving or having received and failed bevacizumab. * Combination of indoximod and temozolomide with stereotactic radiation. Ancillary studies will be conducted to assess the correlation between intra-tumoral IDO expression or serum biomarkers (immune monitoring) and treatment efficacy. If the current study shows an acceptable safety profile and suggests preliminary evidence of activity, this will provide the justification for subsequent randomized phase 2 studies in refractory glioblastoma multiforme (GBM).