- Bayesian multi-stage, multi-cohort design will be used to conduct this phase II trial in patients with Ependymoma, Medulloblastoma, Pineoblastoma, Choroid Plexus Carcinoma or Papilloma, Chordoma, Gliomatosis, Brainstem Glioma, Midline Glioma, ATRT, Malignant or Atypical Meningioma or Gliosarcoma or Primary Brain Sarcoma.