Karenitecin in Treating Patients With Recurrent Malignant Glioma

DISEASE CHARACTERISTICS: Histologically confirmed anaplastic astrocytoma, anaplastic oligodendroglioma, or glioblastoma multiforme Progressive or recurrent disease previously treated with radiotherapy with or without chemotherapy Prior low-grade disease that progressed to high-grade after therapy allowed Measurable disease by MRI or CT scan PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 60-100% Life expectancy: Not specified Hematopoietic: Absolute neutrophil count at least 1,500/mm^3 Platelet count at least 100,000/mm3 Hemoglobin at least 8.5 g/dL Hepatic: Bilirubin no greater than 1.5 mg/dL Transaminases no greater than 4 times upper limit of normal Renal: Creatinine no greater than 1.7 mg/dL Other: No other malignancy within the past 5 years except curatively treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix or breast No serious concurrent infection No other medical illness that would preclude study Negative pregnancy test Not pregnant or nursing Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: See Disease Characteristics At least 3 weeks since prior chemotherapy (6 weeks for nitrosoureas) and recovered No more than 1 prior chemotherapy regimen Endocrine therapy: Must be on stable dose of steroids for at least 5 days Radiotherapy: See Disease Characteristics At least 3 months since prior radiotherapy and recovered No more than 1 prior course of radiotherapy Surgery: Not specified Other: No other concurrent investigational agents At least 10 days since prior anticonvulsant drugs that induce hepatic metabolic enzymes