Window Trial of Fluorescently Labeled Nivolumab-IRDye800 (Nivo800) in High Grade Glioma (HGG)

Inclusion Criteria:

1. Written informed consent

2. Age ≥ 18 years

3. Patient must have imaging of highly suspicious high grade glioma (HGG)

4. Patients for whom surgical craniotomy is planned as standard of care (SOC)

5. Adequate hematologic and end-organ function appropriate for surgical resection andanesthesia (within 30 days of infusion) WBC ≥ 2,000 (mcl) AST 9-80 (IU/L) ALT 7-110 (IU/L) BUN 6-50 (mg/dL) Creatinine 0.5-3.0 (mg/dL) Negative hepatitis B surfaceantigen (HBsAg) test at screening

Exclusion Criteria:

1. Patients not eligible for SOC surgical resection

2. Active or history of autoimmune disease or immune deficiency, including, but notlimited to, myasthenia gravis, myositis, autoimmune hepatitis, systemic lupuserythematosus, rheumatoid arthritis, inflammatory bowel disease, antiphospholipidantibody syndrome, Wegener granulomatosis, Sjögren syndrome, Guillain-Barrésyndrome, or multiple sclerosis with the following exceptions: Patients with a history of autoimmune-related hypothyroidism who are onthyroid-replacement hormone are eligible for the study. Patients with controlled Type 1 diabetes mellitus who are on an insulin regimen areeligible for the study. Patients with eczema, psoriasis, lichen simplex chronicus, or vitiligo withdermatologic manifestations only (e.g., patients with psoriatic arthritis areexcluded) are eligible for the study provided if all the following conditions aremet: Rash must cover < 10% of body surface area Disease is well controlled at baselineand requires only low-potency topical corticosteroids No occurrence of acuteexacerbations of the underlying condition requiring psoralen plus ultraviolet Aradiation, methotrexate, retinoids, biologic agents, oral calcineurin inhibitors, orhigh-potency oral corticosteroids within the previous 12 months

3. History of idiopathic pulmonary fibrosis, organizing pneumonia (e.g., bronchiolitisobliterans), drug-induced pneumonitis, or idiopathic pneumonitis, or evidence ofactive pneumonitis on screening chest CT scan. History of radiation pneumonitis in the radiation field (fibrosis) is permitted.

4. Significant cardiovascular disease (such as New York Heart Association Class II orgreater cardiac disease, myocardial infarction, or cerebrovascular accident) within 3 months prior to initiation of study treatment, unstable arrhythmia, or unstableangina.

5. Severe unresolved infection within 4 weeks prior to initiation of study treatment.

6. Prior allogeneic stem cell or solid organ transplantation

7. History of severe allergic anaphylactic reactions to chimeric or humanizedantibodies or fusion proteins

8. Chronic treatment with systemic immunosuppressive medication in excess ofphysiologic maintenance doses of corticosteroids (>10 mg/day of prednisone orequivalent) (including, but not limited to, corticosteroids, cyclophosphamide,azathioprine, methotrexate, thalidomide, and anti-TNF-a agents), with the followingexceptions: Patients who received acute, systemic immunosuppressant medication or a dose ofsystemic immunosuppressant medication are eligible for the study. Physiologic corticosteroid replacement therapy at doses ≤ 10 mg/day of prednisone orequivalent for adrenal or pituitary insufficiency and in the absence of activeautoimmune disease is permitted. Patients with asthma that requires intermittent use of bronchodilators, inhaledsteroids, or local steroid injections may participate. Patients using topical, ocular, intra-articular, or intranasal steroids (withminimal systemic absorption) may participate. Brief courses of corticosteroids for prophylaxis (e.g., contrast dye allergy) orstudy treatment-related standard premedication is permitted.

9. Pregnant or breastfeeding, or intention of becoming pregnant during study treatmentor within 2 months after the final dose of study treatment.

10. Participants presenting with a baseline QTcF interval > than 480 milliseconds.