Inclusion Criteria:

          1. Participant has the ability to understand and the willingness to provide a signed and
             dated informed consent form.

          2. Participant has the willingness to comply with all study procedures and availability
             for the duration of the study.

          3. Participant is being evaluated for a potential, or known, diagnosis of high grade
             glioma.

          4. Participant is a candidate for brain surgery or has undergone prior surgery and has
             not received any additional treatment for high grade glioma.

          5. Participant is male or female, ≥ 18 years of age.

          6. Participant has a Karnofsky Performance Status (KPS) ≥ 60%:

        Exclusion Criteria:

          1. Participant has received prior anti-cancer treatment for high grade glioma.

          2. Participant has a diagnosis of immunodeficiency or active autoimmune disease.

          3. Participant is receiving chronic systemic steroid therapy in dosing exceeding 8 mg
             daily of dexamethasone equivalent or any other form of immunosuppressive therapy
             within 7 days prior to the first dose of study drug. Note: This is assessed after
             surgery, prior to starting drug treatment.

          4. Participant has received a live vaccine within 28 days prior to the first dose of
             study agent. Examples of live vaccines include, but are not limited to measles, mumps,
             rubella, varicella/zoster (chicken pox), yellow fever, rabies, Bacillus
             Calmette-Guérin (BCG), typhoid vaccine, and intranasal influenza vaccines (e.g.,
             FluMist®).

          5. Participant has a severe or uncontrolled medical disorder that would, in the
             investigator's opinion, impair ability to receive study intervention (i.e.,
             uncontrolled diabetes, chronic renal disease, chronic pulmonary disease or active,
             uncontrolled infection, psychiatric illness/social situations that would limit
             compliance with study requirements).

          6. Participant is a female of childbearing potential who is pregnant or nursing.

          7. Participant has a history of thrombotic or hemorrhagic stroke or myocardial infarction
             within 6 months.

          8. Participant has a history of intestinal perforations, fistula, hemorrhages, and/or
             hemoptysis ≤ 6 months prior to first study treatment.

          9. Participant has active gastrointestinal bleeding.

         10. Participant has uncontrolled hypertension (systolic blood pressure ≥ 160 mm Hg and/or
             diastolic blood pressure ≥ 90 mm Hg).