Safety and Efficacy Study of TH-302 CNS Penetration in Recurrent High Grade Astrocytoma Following Bevacizumab

The Primary Objectives are: * To determine the extent by which TH-302 is able to penetrate the blood brain barrier and affect tumor tissue * To assess the safety of single dose TH-302 in patients with high grade glioma undergoing surgery * To assess the safety of TH-302 in combination with bevacizumab for patients with high grade glioma * To determine the MTD and DLT(s) of TH-302 in combination with bevacizumab The Secondary Objectives are: To determine the progression-free survival with or without debulking craniotomy for patients treated with combination bevacizumab and TH-302 following recurrence on single agent bevacizumab