A Phase 2 Trial of High-Dose Ascorbate in Glioblastoma Multiforme

This clinical trial evaluates adding high-dose ascorbate (vitamin C) to standard of care treatment of glioblastoma multiforme (a type of brain tumor) in adults. All subjects will receive high-dose ascorbate in addition to the standard treatment.

Standard treatment for glioblastoma multiforme (GBM) involves maximum safe surgical resection followed by radiation combined with temozolomide (a chemotherapy pill you take by mouth). After radiation, patients receive additional cycles of temozolomide (adjuvant chemotherapy). Participants will: * receive high doses of intravenous (IV) ascorbate three times a week during the combined radiation and chemotherapy phase * receive high doses of intravenous (IV) ascorbate twice a week during adjuvant chemotherapy (after radiation) * complete health-related quality of life questionnaires pre-radiation, 4 weeks into radiation, 4 weeks after radiation, and then every 3 months. In addition, patients will complete neurocognitive testing pre-radiation, 4 weeks into radiation, 4 weeks after radiation, and approximately 9 months after initiating radiation therapy. The adjuvant chemotherapy portion of this study lasts for 6 months. After that is completed, participants will go back to standard therapy for their cancer. Participants will continue to have life-long follow-up for this study.