Carboplatin and Irinotecan in Treating Children With Refractory Solid Tumors

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed solid tumor, including primary brain tumor * Progressive disease on standard therapy or for which no standard therapy exists * No symptomatic brain metastases PATIENT CHARACTERISTICS: Age: * 1 to 21 Performance status: * Lansky 50-100% (age 10 and under) * Karnofsky 50-100% (over age 10) Life expectancy: * At least 8 weeks Hematopoietic: * Absolute neutrophil count greater than 1,000/mm3 * Platelet count greater than 100,000/mm3 Hepatic: * Bilirubin no greater than 1.5 mg/dL * ALT no greater than 2.5 times upper limit of normal Renal: * Glomerular filtration rate at least 30 mL/min Other: * No active infection * No serious uncontrolled medical disorder * No psychiatric disorder or other disorder that would preclude study * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: * At least 6 months since prior allogeneic bone marrow transplantation without evidence of acute or chronic graft versus host disease * At least 3 months since prior autologous bone marrow or peripheral blood stem cell transplantation * At least 4 weeks since prior immunotherapy and recovered * No concurrent immunotherapy Chemotherapy: * No more than 3 prior chemotherapy regimens * At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered * No other concurrent chemotherapy Endocrine therapy: * Concurrent hormone replacement therapy or oral contraceptives allowed * No other concurrent hormonal therapy Radiotherapy: * At least 4 weeks since prior radiotherapy (including for brain metastases) and recovered * No concurrent radiotherapy Surgery: * Not specified Other: * No other concurrent investigational anticancer drugs * No other concurrent antitumor therapy * No concurrent anticonvulsants (e.g., phenytoin, phenobarbital, or carbamazepine) except gabapentin (Neurontin)