Temozolomide Plus Irinotecan in Treating Patients With Recurrent Malignant Glioma

DISEASE CHARACTERISTICS: * Histologically confirmed supratentorial malignant primary glioma of one of the following subtypes: * Glioblastoma multiforme * Anaplastic astrocytoma * Anaplastic oligodendroglioma * Mixed malignant glioma * Original histology of low-grade glioma allowed if subsequent histological confirmation of malignant glioma * Measurable recurrent or residual primary disease by MRI * Lesions with clearly defined margins * Evidence of tumor recurrence or progression by MRI or CT scan * Confirmation of true progressive disease by PET or thallium scan, magnetic resonance spectroscopy, or surgical documentation after prior interstitial brachytherapy or stereotactic radiosurgery * No more than 3 relapses after prior chemotherapy/cytotoxic therapy (including polifeprosan 20 with carmustine implant) for phase I and no more than 2 relapses for phase II PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * Karnofsky 60-100% Life expectancy: * Not specified Hematopoietic: * WBC at least 3,000/mm\^3 * 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 no greater than 1.5 mg/dL * SGOT no greater than 2 times upper limit of normal Renal: * Creatinine no greater than 1.5 mg/dL Cardiovascular: * No uncontrolled hypertension, unstable angina, or symptomatic congestive heart failure * No myocardial infarction within the past 6 months * No serious uncontrolled cardiac arrhythmia Other: * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No mental incapacitation * HIV negative * No AIDS-related disease * No significant ongoing alcoholism or substance abuse * No severe nonmalignant systemic disease * No active infection * No other severe disease that would preclude study PRIOR CONCURRENT THERAPY: Biologic therapy: * At least 1 week since prior interferon or thalidomide and recovered * No concurrent anticancer immunotherapy * No concurrent sargramostim (GM-CSF) * No concurrent prophylactic filgrastim (G-CSF) during first course of study therapy Chemotherapy: * See Disease Characteristics * Recovered from prior chemotherapy * At least 2 weeks since prior vincristine * At least 3 weeks since prior procarbazine * At least 4 weeks since prior cytotoxic chemotherapy (6 weeks for nitrosourea) * Prior radiosensitizers allowed * No prior temozolomide or irinotecan * No other concurrent anticancer chemotherapy Endocrine therapy: * At least 1 week since prior tamoxifen and recovered * No concurrent anticancer hormonal therapy * Phase II: * Non-increasing dose of corticosteroids allowed Radiotherapy: * See Disease Characteristics * At least 4 weeks since prior radiotherapy and recovered * No concurrent anticancer radiotherapy Surgery: * See Disease Characteristics * At least 1-3 weeks since prior surgical resection and recovered Other: * At least 1 week since prior noncytotoxic agents (e.g., isotretinoin) and recovered * Concurrent enzyme-inducing anti-epileptic drugs with or without steroids allowed * No concurrent valproic acid as a single agent * No concurrent medication that would preclude study (e.g., nonsteroidal immunosuppressive agents) * No other concurrent investigational drugs * No concurrent participation in other clinical study