Oral ONC201 in Recurrent GBM, H3 K27M Glioma, and Midline Glioma

- leukocytes ≥ 3,000/mcL

- absolute neutrophil count ≥ 1,500/mcL

- platelets ≥ 100,000/mcL

- hemoglobin > 8.0 mg/dL

- total bilirubin < 2.0 x upper limit of normal

- AST (SGOT)/ALT (SGPT) ≤2.5 × upper limit of normal creatinine OR creatinine clearance ≥60 mL/min/1.73 m2 for patients with creatinine levels above normal. CT or MRI within 14 days prior to start of study drug. Corticosteroid dose must be stable or decreasing for at least 5 days prior to the scan. For Arm B: Corticosteroid dose must be stable or decreasing for at least 2 weeks prior to study entry. The effects of ONC201 on the developing human fetus are unknown. For this reason, women of childbearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately. Male subjects should agree to use adequate method of contraception starting with the first dose of study therapy through 120 days after the last dose of therapy. Archival tissue for evaluation of correlative objectives (if available). Archival tissue is required for Arms B and C. Ability to understand and the willingness to sign a written informed consent document.