Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed primary grade 3 or 4 malignant glioma of 1 of the following
types:

- Glioblastoma multiforme

- Gliosarcoma

- Anaplastic astrocytoma

- Anaplastic oligodendroglioma

- Patients with recurrent disease whose original diagnostic pathology confirmed
malignant glioma will not need re-biopsy

- Measurable recurrent or residual primary disease on contrast-enhanced MRI or CT scan

- Failed ≥ 1 prior chemotherapy regimen (with or without radiotherapy)

PATIENT CHARACTERISTICS:

- Karnofsky performance status 60-100%

- Hematocrit > 29%

- Absolute neutrophil count > 1,500/mm^3

- Platelets > 125,000/mm^3

- Serum SGOT and bilirubin < 1.5 times upper limit of normal

- Creatinine < 1.5 mg/dL

- Urine protein:creatinine ratio ≤ 1.0

- Blood pressure ≤ 150/100 mmHg

- No unstable angina

- No New York Heart Association class II or greater congestive heart failure

- No myocardial infarction within the past 6 months

- No stroke within the past 6 months

- No clinically significant peripheral vascular disease

- No evidence of bleeding diathesis or coagulopathy

- No significant traumatic injury within the past 28 days

PRIOR CONCURRENT THERAPY:

- At least 4 weeks must have elapsed since prior chemotherapy or radiotherapy unless
there is unequivocal evidence of tumor progression

- At least 6 weeks since prior surgical resection

- No previous major surgical procedures or open biopsies within 28 days prior to study
entry

- No previous minor surgical procedures, fine needle aspirations, or core biopsies
within 7 days prior to study entry

- No anticipated need for major surgical procedures during the course of the study

- No concurrent aspirin, non-steroidal anti-inflammatory drugs, or clopidogrel