∙ 1a. Arm C only: Participants undergoing resection for a suspected newly diagnosed WHO Grade 4 glioma. Participants will also need to have radiation planned as part of the post-surgical treatment plan; OR,

∙ 1b. Arms A and B only: Participants who have had a prior resection of diagnosed glioma (2021 WHO grade IV), defined as participants who have progressed on or following standard therapy, which includes maximal surgical resection, temozolomide, and fractionated radiotherapy. Participants will also need to have radiation planned as part of the post-surgical treatment plan.

∙ 2\. Participants must have measurable disease preoperatively, defined as at least 1 contrast-enhancing lesion, with 2 perpendicular measurements of at least 1 cm.

∙ 3\. Provision of signed and dated, written informed consent (personally or by the legally authorized representative, if applicable) prior to any study specific procedures, sampling and analyses.

∙ 4\. Age ≥18 at time of consent. 5. Have a performance status (PS) of ≤2 on the Eastern Cooperative Oncology (Group (ECOG) scale1.

∙ 6\. Ability to swallow oral medications. 7. Participant has adequate bone marrow and organ function as defined by the following laboratory values (as assessed by the local laboratory for eligibility):

• Adequate bone marrow function:

‣ absolute neutrophil count ≥1,500/mcL

⁃ Platelets (at time of surgery) ≥100,000/mcL

⁃ hemoglobin ≥9.0 g/dL Participants may receive erythrocyte transfusions to achieve this hemoglobin level at the discretion of the investigator. Initial treatment must not begin earlier than the day after the erythrocyte transfusion.

• Adequate hepatic function:

• o total bilirubin ≤1.5 X ULN. Participants with Gilbert's syndrome with a total bilirubin ≤2.0 times ULN and direct bilirubin within normal limits are permitted.

• o AST(SGOT) ≤2.5 X institutional ULN

• o ALT(SGPT) ≤2.5 X institutional ULN

• Adequate pancreatic function:

• o Amylase within normal limits (WNL)

• o Lipase within normal limits (WNL)

• Adequate renal function:

‣ Serum creatinine ≤1.5 X ULN or estimated creatinine clearance ≥ 60 mL/min (calculated using Institutional standard method) 8. Participants with tumor-induced seizures must be well-controlled on a stable anti-epileptic treatment.

‣ 9\. Participants must be willing to receive prophylaxis with levetiracetam for the duration of study drug administration (or alternative anti-epileptic if agreed with Medical Monitor) 10. Confirmed negative serum pregnancy test (β-hCG) before starting study treatment or participant who is no longer of childbearing potential due to surgical, chemical, or natural menopause.

‣ 11\. For females of reproductive potential: use of highly effective contraception and agreement to use such a method during study participation until the end of treatment administration and for 16 weeks after the last dose of study drug.

‣ 12\. For males of reproductive potential: use of condoms or other methods to ensure effective contraception with partner until the end of treatment administration and for 16 weeks after the last dose of study drug.

‣ 13\. Agreement to adhere to Lifestyle Considerations (see Section 5.3) throughout study duration.