Could High-Dose vitamin c boost brain cancer treatment?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Ability to understand and willingness to sign informed consent (power of attorney and/or legally authorized representatives cannot sign on behalf of the patient) * Patients must have newly diagnosed (i.e., within 5 weeks), histologically or cytologically confirmed glioblastoma multiforme. * Diagnosis must be made by surgical biopsy or excision. * Therapy must begin ≤ 5 weeks after surgery or biopsy * Age ≥ 18 years * ECOG performance status 0-2. (KPS \> 50) * Absolute neutrophil count (ANC) ≥ 1500 cells per mm3 * Platelets ≥ 100,000 per mm3 * Hemoglobin ≥ 8 g/dL * Creatinine ≤ 2.0 mg * Total bilirubin ≤ 1.5 mg/dL * ALT ≤ 3 times the institutional upper limit of normal * AST ≤ 3 times the institutional upper limit of normal * Tolerate one test dose (15g) of ascorbate. * Not pregnant. Exclusion Criteria: * Recurrent high grade glioma * G6PD (glucose-6-phosphate dehydrogenase) deficiency. * Patients actively receiving insulin or using a finger-stick glucometer daily for blood glucose measurements * History of allergic reactions attributed to compounds of similar chemical or biologic composition to temozolomide. * Significant co-morbid central nervous system disease, including but not limited to, multiple sclerosis. * Patients who are on the following drugs and cannot have a drug substitution: warfarin, flecainide, methadone, amphetamines, quinidine, and chlorpropamide. * Known active concurrent malignancy, as determined by treating physicians. * Patients who have received prior chemotherapy (including Gliadel wafers) for the current glioma. * Prior radiation therapy to the head or neck resulting in overlap of RT fields. * Patients receiving any other investigational agents (imaging agents are acceptable) * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection that would result in a hospital stay or delay of treatment, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements or impact patient safety. * Pregnant women. * Breastfeeding women. * Known HIV-positive individuals. High-dose ascorbate acid is a known CYP450 3A4 inducer, which results in lower serum levels of antiretroviral drugs.