Carboplatin, Melphalan, Etoposide Phosphate, Mannitol, and Sodium Thiosulfate in Treating Patients With Previously Treated Brain Tumors

Inclusion Criteria:

* Subjects with pathologic evidence of an anaplastic oligodendroglioma or mixed glioma (i.e. oligoastrocytoma) are eligible; histopathologic diagnosis will be made using World Health Organization classification criteria; to qualify as a mixed tumor there must be a minimum of 25% oligodendroglial element
* Surgical procedure may have been complete resection, partial resection, or biopsy
* Subjects must have had prior treatment with temozolomide; at least 28 days must have elapsed since completion of temozolomide or other chemotherapy
* If subject has not undergone radiation therapy, then subject must have undergone prior consultation with a radiation oncologist (who is not an investigator on this study); if the subject has undergone radiation therapy, then at least 14 days must have elapsed since completion of radiation
* Subjects performance status must be (Karnofsky performance status \[KPS\] greater than or equal to 50; Eastern Cooperative Oncology Group \[ECOG\] less than or equal to 2)
* White blood cell count \>= 2.5 x 10\^3/mm\^3
* Absolute granulocyte count \> 1.5 x 10\^3/mm\^3
* Platelets \>= 100 x 10\^3/mm\^3
* Serum creatinine \< 1.5 x upper limit of normal
* Bilirubin \< 1.5 x upper limit of normal
* Subjects baseline serum glutamic oxaloacetic transaminase (SGOT)/serum glutamate pyruvate transaminase (SGPT) must be \< 2.5 x institutional upper limit of normal
* Subjects must sign a written informed consent in accordance with institutional guidelines
* The effects of carboplatin, melphalan and etoposide phosphate on the developing human fetus at the recommended therapeutic dose are unknown. For this reason and because these agents as well as other therapeutic agents used in this trial are known to be teratogenic. Sexually active women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study treatment and for the duration of study treatment; should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately

Exclusion Criteria:

* Subjects with radiographic signs of excessive intracranial mass effect with associated rapid neurologic deterioration, and/or spinal cord block
* Subjects at significant risk for general anesthesia
* Subjects with uncontrolled (over the last 30 days) clinically significant confounding medical conditions
* Subject is pregnant, has a positive serum human chorionic gonadotropin (hCG) or is lactating
* Subjects who have contraindications to carboplatin, melphalan, etoposide phosphate, or sodium thiosulfate