Combination Intraventricular Chemotherapy Pilot Study: 5-Azacytidine (5-AZA) and Trastuzumab Infusions Into the Fourth Ventricle or Resection Cavity in Children and Adults with Recurrent or Residual Posterior Fossa Ependymoma

Inclusion Criteria: * Patients with histologically verified ependymoma, with recurrence or progression anywhere in the brain and/or spine. Patients are also eligible if they have refractory disease, which will be defined as residual tumor which has not been completely cleared despite prior treatments. To be eligible, patients' disease must have originated in the posterior fossa of the brain * Patient must have either measurable or evaluable tumor as assessed by MRI of the brain and total spine * An implanted catheter in the fourth ventricle or posterior fossa tumor cavity attached to a ventricular access device or agreement to have one placed. * A minimum of 4 weeks between any prior radiation treatments or bevacizumab infusions and first infusion of 5-azacytidine or trastuzumab infusions. A minimum of 2 weeks between last dose of any other systemic chemotherapy and first infusion of 5-azacytidine or Trastuzumab into fourth ventricle * Life expectancy of at least 12 weeks in the opinion of the principal investigator * Lansky score of 50 or greater if ≤16 years of age or Karnofsky score of 50 or greater if \> 16 years of age * Existing neurological deficits must have been stable for a minimum of 1 week prior to study enrollment * Patients must have recovered from the acute toxic effects of all prior anticancer chemotherapy * Adequate bone marrow function defined by peripheral absolute neutrophil count (ANC) ≥ 500/µL, platelet count ≥ 50,000/µL (transfusion independent), and h…