Topotecan and Thalidomide in Treating Patients With Recurrent or Refractory Malignant Glioma

DISEASE CHARACTERISTICS: * Histologically confirmed recurrent or progressive supratentorial glioblastoma or anaplastic astrocytoma * Measurable disease by MRI or CT scan * No gliomatosis cerebri, anaplastic oligodendroglioma, or anaplastic oligoastrocytoma * Concurrent registration for the System for Thalidomide Education and Prescribing Safety (S.T.E.P.S.) program PATIENT CHARACTERISTICS: Age: * Over 18 Performance status: * ECOG 0-2 Life expectancy: * Not specified Hematopoietic: * WBC greater than 4,000/mm\^3 * Platelet count greater than 100,000/mm\^3 Hepatic: * Bilirubin less than 2.0 mg/dL Renal: * Creatinine less than 1.6 mg/dL Other: * No other concurrent malignancy except curatively treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use 2 methods of effective contraception 1 month prior to, during, and for 1 month after study participation PRIOR CONCURRENT THERAPY: Biologic therapy: * Not specified Chemotherapy: * No more than 2 prior chemotherapy regimens in adjuvant or metastatic setting * At least 4 weeks since prior chemotherapy Endocrine therapy: * Not specified Radiotherapy: * Not specified Surgery: * Not specified Other: * Concurrent anticonvulsants allowed