OBJECTIVES: Primary * Determine the maximum tolerated dose (MTD) of gimatecan in patients with recurrent or progressive primary malignant glioma treated with or without concurrent enzyme-inducing anticonvulsant drugs. * Determine whether this drug has sufficient activity to warrant further development in these patients. (phase II) Secondary * Determine the qualitative and quantitative toxic effects of this drug in these patients. * Determine the pharmacokinetic behaviors of this drug in these patients. * Correlate the principal toxic effects with the pertinent pharmacokinetic parameters of this drug in these patients. * Determine the antitumor activity of this drug in these patients. OUTLINE: This is an open-label, dose-escalation, multicenter study. Patients are stratified according to the concurrent use of enzyme-inducing anticonvulsant drugs (yes vs no). * Phase I: Patients receive oral gimatecan once daily on days 1-5. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. Cohorts of 3-6 patients receive escalating doses of gimatecan until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose-limiting toxicity. * Phase II: Patients receive gimatecan as in phase I at the MTD. Patients are followed for at least 1 month and then every 2 months thereafter. PROJECTED ACCRUAL: Approximately 30-83 patients (30-42 for phase I \[15-21 per stratum\] and 21-41 for phase II) will be accrued for this study within 24 months.
DISEASE CHARACTERISTICS: * Histologically confirmed malignant glioma (glioblastoma multiforme, anaplastic astrocytoma, or anaplastic oligodendroglioma) * Recurrent or progressive primary CNS neoplasm by contrast-enhanced MRI * Tumor progression after prior surgery, radiotherapy, or chemotherapy * Measurable or evaluable disease * Failed prior standard curative or palliative therapy (phase I only) PATIENT CHARACTERISTICS: Age * 18 and over Performance status * Karnofsky 60-100% Life expectancy * At least 3 months Hematopoietic * Absolute neutrophil count ≥ 2,000/mm\^3 * Platelet count ≥ 100,000/mm\^3 Hepatic * SGPT and SGOT ≤ 1.5 times upper limit of normal (ULN) (3 times ULN if liver metastases are present) * Alkaline phosphatase ≤ 2.5 times ULN (5 times ULN if liver metastases are present) * Bilirubin normal Renal * Creatinine ≤ 1.5 times ULN Cardiovascular * No myocardial infarction with the past year * No heart failure (including cardiac insufficiency controlled by digitalis and diuretics) * No irreversible arrhythmias requiring permanent medication * No uncontrolled hypertension Gastrointestinal * No gastrointestinal dysfunction that would alter absorption or motility, such as any of the following: * Active peptic ulcer * Inflammatory bowel disease * Known intolerance to lactose * Malabsorption syndromes * Intestinal sub-occlusion Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective barrier contraception * No active infection * No mentally incapacitated patients * No other concurrent severe disease that would preclude study participation PRIOR CONCURRENT THERAPY: Biologic therapy * No concurrent immunotherapy Chemotherapy * See Disease Characteristics * At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas) * No more than 1 prior chemotherapy regimen * No other concurrent chemotherapy Endocrine therapy * Concurrent corticosteroids allowed if dose stable for the past 2 weeks * No concurrent hormonal therapy Radiotherapy * See Disease Characteristics * At least 4 weeks since prior radiotherapy * No concurrent radiotherapy Surgery * See Disease Characteristics * At least 3 weeks since prior surgical resection * No prior gastrointestinal surgery that would affect drug absorption Other * More than 4 weeks since prior participation in any other investigational drug study * More than 72 hours since prior systemic antibiotics * No concurrent H2 antagonists, antacids, or proton pump inhibitors * If any of these therapies are necessary, ≥ 3 hours must elapse after gimatecan administration * No other concurrent anticancer therapy * No other concurrent investigational drugs * No other concurrent immunosuppressive agents