Imatinib Mesylate in Treating Patients With Gliomas

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed glioblastoma multiforme * Recurrent disease by CT scan or MRI * No prior chemotherapy OR * No more than 1 prior chemotherapy regimen in adjuvant setting or for recurrent disease OR * Histologically or cytologically confirmed anaplastic oligodendroglioma, mixed oligoastrocytoma, anaplastic astrocytoma, or recurrent low-grade astrocytoma * Failed prior radiotherapy * No more than 1 prior chemotherapy regimen * Failed adjuvant chemotherapy OR * Failed first-line chemotherapy * At least 1 bidimensionally measurable target lesion * At least 2 cm on contrast-enhanced CT scan or MRI PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * ECOG 0-2 Life expectancy: * Not specified Hematopoietic: * Neutrophil count at least 2,000/mm\^3 * Platelet count at least 100,000/mm\^3 Hepatic: * Bilirubin no greater than 1.5 times upper limit of normal (ULN) * AST and ALT no greater than 2.5 times ULN * Alkaline phosphatase no greater than 2.5 times ULN Renal: * Creatinine less than 1.7 mg/dL Cardiovascular: * Cardiac function normal * No ischemic heart disease within the past 6 months * Normal 12-lead ECG Other: * No other prior or concurrent malignancy except cone-biopsied carcinoma of the cervix or adequately treated basal cell or squamous cell skin cancer * No unstable systemic disease * No active uncontrolled infection * No psychological, familial, sociological, or geographical condition that would preclude study compliance * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception during and for 3 months after study PRIOR CONCURRENT THERAPY: Biologic therapy: * No concurrent anticancer biologic agents * No concurrent cytokines (e.g., filgrastim \[G-CSF\] or sargramostim \[GM-CSF\]) Chemotherapy: * See Disease Characteristics * At least 4 weeks since prior chemotherapy (6 weeks for nitrosourea) * No concurrent chemotherapy Endocrine therapy: * Must be on stable or decreasing dose of corticosteroids for at least 2 weeks Radiotherapy: * See Disease Characteristics * At least 3 months since prior brain irradiation * No prior high-dose radiotherapy (more than 65 Gy), stereotactic radiosurgery, or internal radiotherapy unless the recurrence is histologically confirmed * No concurrent radiotherapy Surgery: * Prior surgery for primary brain tumor within the past 3 months allowed provided one of the following conditions are present: * Postoperative imaging within 72 hours after surgery shows a clearly limited target lesion of at least 2 cm * Postoperative follow-up shows a progressive and measurable target lesion * A second measurable target lesion is present outside the surgical area Other: * No concurrent warfarin or other anticoagulants * No other concurrent anticancer agents * No other concurrent investigational agents