Antineoplaston Therapy in Treating Children With Primary Malignant Brain Tumors

DISEASE CHARACTERISTICS: * Histologically confirmed incurable primary malignant brain tumor that has progressed, recurred, or persisted after initial therapy (must have failed standard therapy). * Evidence of residual tumor by MRI performed within two weeks prior to study entry PATIENT CHARACTERISTICS: Age: * 6 months to 17 years Performance status: * Karnofsky 60-100% Life expectancy: * At least 2 months Hematopoietic: * WBC at least 1,500/mm\^3 * Platelet count greater than 50,000/mm\^3 Hepatic: * No hepatic failure * Bilirubin no greater than 2.5 mg/dL * SGOT/SGPT no greater than 5 times upper limit of normal Renal: * Creatinine no greater than 2.5 mg/dL Cardiovascular: * No severe heart disease * No uncontrolled hypertension Pulmonary: * No severe lung disease Other: * Not pregnant or nursing * Fertile patients must use effective contraception during and for 4 weeks after study participation * No serious active infections or fever * No other serious concurrent disease PRIOR CONCURRENT THERAPY: Biologic therapy: * At least 4 weeks since prior immunotherapy and recovered * No concurrent immunomodulating agents Chemotherapy: * At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas) and recovered * No concurrent antineoplastic agents Endocrine therapy: * Recovered from prior endocrine therapy * Concurrent corticosteroids for cerebral edema allowed Radiotherapy: * At least 8 weeks since prior radiotherapy (unless clear radiological evidence of progression) and recovered Surgery: * At least 4 weeks since prior surgery (unless clear radiological evidence of progression) and recovered Other: * No prior antineoplaston therapy