Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed recurrent primary malignant glioma

- Anaplastic astrocytoma

- Glioblastoma multiforme

- Anaplastic oligodendroglioma

- Gliosarcoma

- Anaplastic mixed oligoastrocytoma

- Measurable disease by MRI or CT

- No immediate radiotherapy required

- Neurologically stable for at least 2 weeks prior to study

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- Karnofsky 60-100%

Life expectancy:

- Greater than 12 weeks

Hematopoietic:

- Absolute neutrophil count at least 1,500/mm^3

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

- Hemoglobin at least 10 g/dL

Hepatic:

- Bilirubin less than 1.5 times upper limit of normal (ULN)

- SGOT and SGPT less than 2.5 times ULN

- Alkaline phosphatase less than 2 times ULN

Renal:

- Blood urea nitrogen and creatinine less than 1.5 times ULN

Other:

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- HIV negative

- No other nonmalignant systemic disease

- No acute infection treated with IV antibiotics

- No frequent vomiting or other condition that would preclude oral medication
administration (e.g., partial bowel obstruction)

- No other prior malignancies except surgically cured carcinoma in situ of the cervix
or basal or squamous cell skin cancer

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- No more than 1 prior biologic therapy regimen

Chemotherapy:

- No more than 1 prior chemotherapy regimen

- At least 6 weeks since prior chemotherapy, unless evidence of disease progression

- No prior failure of irinotecan or temozolomide

Endocrine therapy:

- Concurrent corticosteroids allowed

Radiotherapy:

- See Disease Characteristics

- At least 6 weeks since prior radiotherapy, unless evidence of disease progression

Surgery:

- At least 3 weeks since prior surgery, unless evidence of disease progression, and
recovered

Other:

- No concurrent immunosuppressive agents