IDO1 and central nervous system cancer: Secondary objectives include (1) obtaining provisional data regarding potential progression-free and overall survival benefit of M032 in the treatment of canine patients with high grade gliomas, both alone and with added IDO inhibition; (2) establishing baseline (pre-treatment) local and systemic immune profiles and characterizing immune responses referable to M032 administration without and with IDO inhibition; and (3) measuring in situ activity of the M032 virus following inoculation.