Irinotecan Plus Temozolomide in Treating Patients With Recurrent Primary Malignant Glioma

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