DISEASE CHARACTERISTICS: Recurrent brain tumor based on one of the following: Tissue diagnosis if there was a prior diagnosis of astrocytoma or oligodendroglioma or if there is a question of radiation necrosis from prior interstitial brachytherapy Metabolic activity in excess of normal cortex measured by 18-fluorodeoxyglucose uptake on PET One of the following histologic types required: Glioblastoma multiforme Anaplastic astrocytoma Anaplastic oligodendroglioma Anaplastic mixed glioma Tumor progression required, i.e.: 28% increase in contrast-enhancing area or 50% increase in contrast- enhancing volume over at least 4 weeks Measurable disease required No history, surgical findings, or radiographic signs of intratumoral hemorrhage

PATIENT CHARACTERISTICS: Age: Over 15 Performance status: Karnofsky 50%-100% Life expectancy: At least 12 weeks Hematopoietic: WBC at least 3,000 Platelets at least 75,000 Hepatic: Bilirubin less than 1.5 mg/dL AST/ALT less than 3 times normal No history of bleeding disorder No hepatic disease resulting in hospitalization Renal: Creatinine less than 1.5 mg/dL No renal disease resulting in hospitalization Cardiovascular: No ongoing anticoagulation for deep vein thrombosis (DVT) No residual symptoms from DVT after discontinuation of anticoagulation No cardiac disease resulting in hospitalization Pulmonary: No pulmonary disease resulting in hospitalization Other: No peripheral neuropathy of any etiology HIV negative No pregnant or nursing women Adequate contraception required during and for 12 months following protocol therapy

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy for glioblastoma multiforme No more than 1 prior chemotherapy regimen for anaplastic astrocytoma, malignant oligodendroglioma, or malignant mixed glioma At least 4 weeks since chemotherapy (6 weeks since nitrosoureas or mitomycin) Endocrine therapy: Not specified Radiotherapy: Completion of 1 course of conventional external radiotherapy required At least 4 weeks since radiotherapy Surgery: Decompressive surgery for clinically suspected increased intracranial pressure performed prior to entry