Therapy Optimization Trial for the Treatment of Relapsed or Refractory Brain Tumors in Children

Inclusion Criteria: Disease Characteristics * Histologically confirmed Medulloblastoma, cerebral PNET or Ependymoma * Refractory or relapsed disease * Measurable disease by MRI or detection of tumor cells in cerebrospinal fluid Patients characteristics * Performance status ECOG ≥ 3 or Karnofsky Status ≥ 40% * Life expectancy ≥ 8 weeks Hematological: * Absolute leukocyte count ≥ 2.0 x 10\^9 /l * Hemoglobin ≥ 10g/dl * Platelet count ≥ 70 x 10\^9/l Renal: * Creatinine no greater than 1.5 times UNL * No overt renal disease Hepatic: * Bilirubin less than 2.5 times UNL * AST and ALT less than 5 times UNL * No overt hepatic disease Pulmonary: * No overt pulmonary disease Cardiovascular: * No overt cardiovascular disease Other: * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No uncontrolled infection Prior concurrent therapy * More than 2 weeks since prior systemic chemotherapy * More than 4 weeks since prior radiotherapy * No other concurrent anticancer or experimental drugs Examinations required * Examination of lumbar CSF * Cranial and spinal MRI within 14 days prior to start of treatment