Imatinib Mesylate in Treating Patients With Relapsed or Refractory Solid Tumors of Childhood

Inclusion Criteria: Histologically confirmed solid tumors including the following: Ewing's sarcoma Bone or soft tissue primitive neuroectodermal tumor Osteosarcoma Neuroblastoma Desmoplastic small round cell tumor Synovial cell sarcoma Gastrointestinal stromal tumor (GIST) Metastatic pulmonary disease eligible No pleural effusion of any size or definite radiologic evidence of pleural-based disease Recurrent or refractory to conventional therapy GIST eligible at initial presentation Tumor tissue blocks must be available At least 1 measurable lesion At least 20 mm by conventional techniques At least 10 mm by spiral CT scan Lesions assessable only by radionuclide scan are not considered measurable Performance status - Lansky 50-100% (≤ 10 years of age) Performance status - Karnofsky 50-100% (> 10 years of age) At least 2 months Absolute neutrophil count ≥ 1,000/mm^3* Platelet count ≥ 75,000/mm^3* (transfusion independent) Hemoglobin ≥ 8.0 g/dL* (RBC transfusions allowed) Bilirubin ≤ 1.5 times upper limit of normal (ULN) ALT ≤ 2.5 times ULN INR < 1.5 PTT ≤ ULN Fibrinogen ≥ lower limit of normal Creatinine normal for age Glomerular filtration rate ≥ 70 mL/min No uncontrolled infection Not pregnant or nursing Negative pregnancy test Fertile patients must use effective barrier contraception At least 1 week since prior biologic therapy or immunotherapy and recovered At least 1 week since prior growth factors No concurrent immunomodulating agents At least 2 weeks since prior myelosuppressive chemotherapy (4 weeks for nitrosoureas) and recovered No concurrent chemotherapy No concurrent steroids Recovered from prior radiotherapy At least 2 weeks since prior local palliative radiotherapy (small port) At least 3 months since prior craniospinal radiotherapy or radiotherapy to 50% or more of pelvis At least 6 weeks since other prior substantial bone marrow radiation No concurrent radiotherapy during first course of treatment Concurrent palliative radiotherapy to local painful lesions allowed after first course of treatment provided there is no evidence of disease progression and at least 1 measurable lesion remains outside radiation port No concurrent therapeutic doses of warfarin No concurrent anticonvulsants that induce the cytochrome p450 enzyme system (e.g., phenytoin, carbamazepine, and phenobarbital) Concurrent benzodiazepines and gabapentin allowed Concurrent low-molecular weight heparin allowed