SGT-53 in Children With Recurrent or Progressive CNS Malignancies

Inclusion Criteria: * Patients must have a recurrent, progressive, or refractory CNS malignancy for which there are not known curative options. Low-grade glioma, craniopharyngioma, and other non-malignant CNS tumors are excluded. * Tumor must be measureable, defined as a tumor that can be accurately measured in two perpendicular dimensions on MRI. * Patients with metastatic disease are eligible but must have at least one target lesions which is measurable. * Patients must have available archival (formalin-fixed paraffin embedded) or fresh tumor tissue for correlative studies. * Patients must be \>1yrs and \<21 years of age. * Must have recovered from all surgical interventions prior to the start of the Radiation and Chemotherapy Phases. * Patients must have recovered from the acute effects of prior therapy. * There is a maximum of 3 previous myelosuppressive therapy regimens. However, there is no maximum number of therapeutic courses. * Patients must have received their last dose of known myelosuppressive therapy at least three (3) weeks prior to receipt of SGT-53. * Patients must have received their last dose of biological agent \>7 days prior to receipt of SGT-53. * Patients must be far enough from previous irradiation that in the opinion of a radiation oncologist using standard fractionation is deemed to be reasonable from a clinical standard of care perspective. * Patients who are receiving dexamethasone or other corticosteroids must be on a stable or decreasing dose for…