A Safety Study of Pharmacologic Ascorbate and Ferumoxytol in Addition to Standard of Care Chemoradiation in Glioblastoma

Inclusion Criteria: * Willingness and ability to provide informed consent consistent with Good Clinical Practice (i.e., legally authorized representative will not be used / allowed for this study). * Stated willingness to comply with all study procedures for the duration of the study * Aged 18 years or older. * Newly diagnosed (i.e., within 6 weeks), histologically or molecularly confirmed glioblastoma or diffuse midline glioma. * Therapy to begin within 6 weeks of last surgery * Able to take oral medication * ECOG performance status of 0, 1, or 2 (KPS of \>50) * Recommended to receive temozolomide and radiation therapy * Medically fit, as determined by the prescribing oncologists, to undergo temozolomide and radiation therapy. * Agree to use of highly effective contraception from screening until at least 90 days after the last study treatment (study participant should not discontinue contraception until discussing with their treating oncologist(s)). * Not have significant co-morbid central nervous system disease, such as multiple sclerosis. * Agree to Lifestyle Considerations throughout study duration Exclusion Criteria: * Current use of the following drugs and cannot have a drug substitution or decline the drug substitution: warfarin, flecainide, methadone, amphetamines, quinidine, and chlorpropamide. Pharmacologic ascorbic acid may affect urine acidification and, as a result, may affect clearance rates of these drugs. * Current use of antiretroviral drugs (e.g., nelfina…