DISEASE CHARACTERISTICS:

• Diagnosis of any of the following malignant gliomas:

  • Glioblastoma multiforme
  • Anaplastic astrocytoma
  • Grade 3 or greater WHO astrocytic, oligodendroglial, or mixed glial tumors that were initially diagnosed by histologic examination of a tumor specimen obtained from biopsy or resection

• Recurrent disease

  • No more than 3 prior recurrences
• Measurable recurrent or residual primary CNS neoplasm on contrast-enhanced MRI or CT scan
• No evidence of CNS hemorrhage on baseline MRI or CT scan

PATIENT CHARACTERISTICS:

• Karnofsky performance status 60-100%
• Hematocrit > 29%
• Absolute neutrophil count > 1,500/mm³
• Platelet count > 125,000/mm³
• Creatinine < 1.5 mg/dL
• SGOT < 1.5 times upper limit of normal (ULN)
• Bilirubin < 1.5 times ULN
• Not pregnant or nursing
• Fertile patients must use effective contraception
• No active infection
• No significant traumatic injury within the past 28 days

PRIOR CONCURRENT THERAPY:

• At least 6 weeks since prior surgical resection
• More than 28 days since prior major surgical procedure or open biopsy
• More than 7 days since prior minor surgical procedure, fine-needle aspirations, or core biopsies
• At least 6 weeks since prior chemotherapy*
• At least 4 weeks since prior radiotherapy*
• No concurrent immunosuppressive agents
• No concurrent therapeutic anticoagulation
• Concurrent corticosteroids allowed if dose has been stable for 1 week prior to study entry NOTE: * Unless there is unequivocal evidence of progressive disease