PEP-CMV + Nivolumab for Newly Diagnosed Diffuse Midline Glioma/High-grade Glioma and Recurrent Diffuse Midline Glioma/High-grade Glioma, Medulloblastoma, and Ependymoma

Exclusion Criteria

• Pregnant or breast-feeding women will not be entered on this study due to known or unknown risks of fetal and teratogenic adverse events as seen in animal/human studies. Pregnancy tests must be obtained in girls and women who are post-menarchal at least 7 days prior to study enrollment. Males or females of reproductive potential may not participate unless they have agreed to use an effective contraceptive method, which includes abstinence.
• Active infection requiring treatment.
• Patients with malignancy related to HIV or solid organ transplant: known history of HIV, HBV surface antigen positivity or positive HCV antibody are not eligible. Viral testing is not required unless clinically indicated in patients without a known history
• Known immunosuppressive disease.
• Patients with active unrelated systemic illness including but not limited to renal, hepatic cardiac (congestive cardiac failure, myocardial infarction, myocarditis), or moderate to severe pulmonary problems generally defined by need for medical intervention (e.g., oxygen, medications) and/or limiting activities of daily living (generally CTCAE Grade 2 or higher) or shortness of breath with limited exertion are not eligible. Pulmonary conditions include (but are not limited to) COPD, asthma, and hemi-pneumectomy
• Patients receiving concomitant immunosuppressive agents for medical conditions; inhaled corticosteroids for asthma are allowed.
• Patients receiving concomitant tumor-directed therapy.
• Patients receiving any other investigational drug therapy.
• Previous enrollment and treatment on an interventional clinical trial (Stratum 1 only).
• Patients on dexamethasone > 0.1 mg/Kg/day up to maximum dose of 4 mg/day or equivalent.
• Patients with inability to return for follow-up visits or obtain follow-up studies required to assess toxicity to therapy.
• Patients at high risk for imminent neurologic decline due to extensive bulk disease, midline shift, or herniation on MRI. These patients should be discussed with the study chairs.