Study of a Retroviral Replicating Vector Given Intravenously to Patients Undergoing Surgery for Recurrent Brain Tumor

All patients will receive Toca 511, a retroviral replicating vector that expresses the cytosine deaminase (CD) gene, intravenously and then intracranially. CD converts the antifungal 5-fluorocytosine (5-FC) to the anti-cancer drug 5-fluorouracil (5-FU) in cells that have been infected by the Toca 511 vector. Beginning approximately 6 weeks after the second administration of Toca 511,patients will begin 7-day course of oral 5-FC, repeated every 4 weeks for the duration of the study.