Thalidomide, Celecoxib, and Combination Chemotherapy in Treating Patients With Relapsed or Refractory Malignant Glioma

DISEASE CHARACTERISTICS: Histologically confirmed intracranial malignant glioma, including glioblastoma multiforme, gliosarcoma, anaplastic astrocytoma, anaplastic oligodendroglioma, anaplastic mixed oligoastrocytoma, or malignant astrocytoma not otherwise specified Unequivocal evidence of relapsed or refractory disease by MRI or CT scan and/or tumor resection Steroid therapy prior to MRI or CT scan must have been at a stable dose for at least 5 days Failed prior radiotherapy Must have confirmation of true progression rather than radiation necrosis if previously treated with interstitial brachytherapy or stereotactic radiosurgery PATIENT CHARACTERISTICS: Age 18 and over Performance status Karnofsky 60-100% Life expectancy More than 2 months Hematopoietic Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hemoglobin greater than 9 g/dL No history of bleeding disorder Hepatic Bilirubin less than 1.5 mg/dL SGPT less than 2.5 times normal Alkaline phosphatase less than 2.5 times normal Renal Creatinine less than 1.5 times upper limit of normal (ULN) OR BUN less than 1.5 times ULN Cardiovascular No deep vein thrombosis within the past 3 weeks (must be clinically stable) Pulmonary No pulmonary embolism within the past 3 weeks (must be clinically stable) Other No peripheral neuropathy grade 2 or greater No active infection No other serious concurrent medical illness No concurrent illness that may obscure toxicity or dangerously alter drug metabolism No other malignancy within the past 3 years except nonmelanoma skin cancer or carcinoma in situ of the cervix Must participate in the System for Thalidomide Education and Prescribing Safety program Not pregnant or nursing Negative pregnancy test Fertile patients must use 2 forms of effective contraception for 1 month before, during, and for 1 month after study PRIOR CONCURRENT THERAPY: Biologic therapy No prior oral thalidomide or celecoxib for more than 2 months duration Chemotherapy No prior oral etoposide or cyclophosphamide for more than 2 months duration Prior standard-dose IV etoposide and cyclophosphamide allowed Endocrine therapy See Disease Characteristics Concurrent steroids allowed Radiotherapy See Disease Characteristics At least 4 weeks since prior radiotherapy Surgery See Disease Characteristics Prior surgery for relapsed or refractory disease allowed Recovered from prior surgery No concurrent surgery Other No other concurrent investigational agents or treatment No other concurrent anticancer therapy Concurrent antiseizure medications allowed