Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically proven supratentorial malignant primary glioma, including:

- Glioblastoma multiforme

- Anaplastic astrocytoma

- Anaplastic oligodendroglioma

- Anaplastic mixed oligoastrocytoma

- Malignant astrocytoma not otherwise specified

- Benign or malignant meningiomas, including brain and spinal meningiomas

- Patients with meningiomas are excluded from phase II portion of study

- Must have shown unequivocal evidence of tumor recurrence or progression by CT scan or
MRI

- Must have failed prior radiotherapy

- Must have prestudy contrast MRI or contrast CT scan of brain on stable steroid dose
within the past 14 days

- Must be on stable (unchanged) dose of steroids for at least 5 days before scans

- Phase II:

- Must have completed radiotherapy at least 2 months prior to enrollment

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- Karnofsky 60-100%

Life expectancy:

- More than 8 weeks

Hematopoietic:

- WBC at least 2,300/mm^3

- Platelet count at least 100,000/mm^3

- Hemoglobin at least 8 g/dL (transfusion allowed)

Hepatic:

- SGOT less than 2.5 times upper limit of normal

- Bilirubin normal

- No significant active hepatic disease

Renal:

- Creatinine less than 1.5 mg/dL OR

- Creatinine clearance at least 60 mL/min

- No significant active renal disease

Cardiovascular:

- No uncompensated coronary artery disease on ECG or physical examination

- No history of myocardial infarction or severe/unstable angina within the past 6
months

- No deep venous or arterial thrombosis within the past 3 months

Pulmonary:

- No pulmonary embolism within the past 3 months

Other:

- Not pregnant or nursing

- Fertile patients must use effective contraception during and for 2 months after study

- No other serious concurrent illness

- No significant active psychiatric disease

- No diabetes mellitus with severe peripheral vascular disease

- No other malignancy within the past 3 years except nonmelanoma skin cancer or
carcinoma in situ of the cervix

- No serious active infection

- No other concurrent disease that would obscure toxic effects or dangerously alter
drug metabolism

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- At least 3 weeks since prior biologic therapy (e.g., interferon) and recovered

- No concurrent immunotherapy

Chemotherapy:

- Phase I:

- No more than 2 prior chemotherapy regimens for recurrent disease

- Phase II:

- No more than 1 prior chemotherapy regimen for recurrent disease

- At least 2 weeks since prior vincristine

- At least 6 weeks since prior nitrosoureas

- At least 3 weeks since prior procarbazine

- Recovered from prior chemotherapy

- No concurrent chemotherapy

Endocrine therapy:

- See Disease Characteristics

- At least 3 weeks since prior endocrine therapy (e.g., tamoxifen) and recovered

Radiotherapy:

- See Disease Characteristics

- No concurrent radiotherapy

Surgery:

- Recovered from prior surgery

- Recent prior resection of recurrent or progressive tumor allowed

Other:

- No other concurrent investigational agents