After 16 patients with recurrent GBM are treated, an interim analysis will be conducted. If 6 or more patients have experienced unacceptable toxicity, accrual of patients in this patient group will be terminated. Otherwise, patient accrual will continue. If 9 or more of the total 32 patients experience unacceptable toxicity, the treatment regimen will be considered to have an unacceptable toxicity profile. The type I and II error rates associated with this testing are 0.053 and 0.053, respectively.