Combination Chemotherapy With or Without Sodium Thiosulfate in Preventing Low Platelet Count While Treating Patients With Malignant Brain Tumors

Inclusion Criteria: Subjects with histologically confirmed high-grade glioma are eligible; diagnosis of high-grade glioma will be made on the basis of needle biopsy, open biopsy, or surgical resection Subjects may have had prior focal or systemic radiation or chemotherapy; at least 14 days must have elapsed since radiation treatment and 28 days since prior chemotherapy Performance status (Eastern Cooperative Oncology Group [ECOG]) must be less than or equal to 2 (Karnofsky greater than or equal to 50) White blood cell count >= 2.5 x 10^3/mm^3 Absolute granulocyte count >= 1.2 x 10^3/mm^3 Platelets >= 100 x 10^3/mm^3 Creatinine < 1.8 Bilirubin < 2.0 Baseline aspartate aminotransferase (AST)/alanine aminotransferase (ALT) serum glutamic oxaloacetic transaminase (SGOT)/serum glutamate pyruvate transaminase (SGPT) must be < 2.5 x institutional upper limits of normal Subject (or legal guardian) must sign a written informed consent in accordance with institutional guidelines Sexually active women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; or abstinence) prior to study treatment and for the duration of study treatment; should a female become pregnant or suspect she is pregnant while participating in this study, she should inform the investigator Exclusion Criteria: Subjects with rapidly progressing central nervous system (CNS) disease with associated neurological deterioration Subjects with uncontrolled (over the last 30 days) clinically significant confounding medical conditions such as congestive heart failure Subjects who are pregnant, have a positive serum human chorionic gonadotropin (hCG) or are lactating Subjects who have contraindications to carboplatin, cyclophosphamide, etoposide phosphate, or sodium thiosulfate