Phase I Rindopepimut After Conventional Radiation in Children w/ Diffuse Intrinsic Pontine Gliomas

Inclusion Criteria: 3.1.1 Patients must be at least 3 years of age and ≤ 18 years of age at the time of study enrollment. 3.1.2 Patients must have clinical findings and neuroradiographic findings consistent with diffuse intrinsic pontine glioma. Histologic confirmation of diagnosis is not required for diffuse intrinsic pontine gliomas. A copy of the MRI must be submitted for verification of eligibility. 3.1.3 Patients must have received conventional radiation therapy of total radiation dosage ranging from 5400 to 6000 cGy administered in fractions of 150 to 200 cGy over 6 weeks. 3.1.4 Treatment must start 14 to 28 days after completion of conventional radiation 3.1.5 Patients receiving systemic corticosteroid therapy must be on a tapering or stable low (2 mg twice daily) dose of dexamethasone two weeks after conventional radiation. 3.1.6 Patients life expectancy must be greater or equal to 8 weeks. 3.1.7 Patients must have a performance status (Lansky or Karnofsky) ≥ 50. 3.1.8 Platelet count ≥ 100,000/ mm3. 3.1.9 Hemoglobin ≥ 10 g/dL. 3.1.10 Creatinine ≤ 2.0 mg/dL. 3.1.11 Serum bilirubin ≤ 5.0 mg/dL. 3.1.12 If female, patients of childbearing potential must have a negative serum β-hCG pregnancy test. 3.1.13 Both male and female patients must agree to use hormonal or barrier birth control with spermicidal gel to avoid pregnancy during the study. 3.1.14 The patient and/or their guardian must have the ability to understand and the willingness to sign a written informed consent document. Exclusion Criteria 3.2.1 Prior therapy for diffuse intrinsic pontine glioma, aside from surgery, conventional radiation, and temozolomide. 3.2.2 Use of any experimental drug for any reason within the 60 days prior to treatment. 3.2.3 Active infection requiring treatment. 3.2.4 Known medical condition that, in the opinion of the Investigator, would compromise the patient's ability to participate in the study. This would include chronic active hepatitis infection, known immunosuppressive disease or concurrent neurodegenerative disease. 3.2.5 Known allergy or hypersensitivity to any of the components of the vaccine treatment, including GM-CSF, yeast derived products, or a history of anaphylactic reactions to shellfish proteins. 3.2.6 Pregnant women and women who are breast-feeding.