This is a multicenter, randomized, open-label phase 2/3 study of Toca 511 and Toca FC versus standard of care that comprises Investigator's choice of single agent chemotherapy (lomustine or temozolomide) or bevacizumab administered to subjects undergoing resection for first or second recurrence (including this recurrence) of GBM or AA. Subjects meeting all of the inclusion and none of the exclusion criteria will be randomized prior to surgery in a 1:1 ratio to receive either Toca 511 and Toca FC (Experimental arm, Arm T) or control treatment with one option of standard of care (Arm SOC). Due to the prognostic influence of molecular subgroups such as isocitrate dehydrogenase mutation, the trial will be stratified based on this determination from the primary pathology or subsequent biopsy known locally or otherwise determined centrally. A second stratification factor is based on the patient's Karnofsky Performance Score (KPS) (70-80 vs 90-100). Further, to account for potential differences in treatment choices for the control arm in regions, the trial will be stratified by geographical region during the randomization process. The study will be conducted in 2 parts; enrollment in the phase 3 will begin after phase 2 results are available.