Gimatecan in Treating Patients With Recurrent or Progressive Primary Malignant Glioma

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