Exatecan Mesylate in Treating Patients With Ewing's Sarcoma, Primitive Neuroectodermal Tumor, or Desmoplastic Small Round Cell Tumor

You may be eligible if

• DISEASE CHARACTERISTICS:
• One of the following histologically confirmed diagnoses:
• * Relapsed or refractory Ewing's sarcoma or primitive neuroectodermal tumor
• * Desmoplastic small round cell tumor
• Measurable disease
• * The following are not considered measurable disease:
• * Ascites
• * Pleural effusion
• * Lytic bone lesions
• No symptomatic brain metastases
• PATIENT CHARACTERISTICS:
• Age
• Any age
• Performance status
• ECOG 0-2 (over 10 years of age)
• Lansky 60-100% (10 years of age and under)
• Life expectancy
• At least 12 weeks
• Hematopoietic
• Absolute neutrophil count at least 750/mm\^3
• Platelet count at least 75,000/mm\^3
• Hemoglobin at least 8.5 g/dL
• Hepatic
• Bilirubin no greater than 2.0 mg/dL
• AST or ALT no greater than 2.5 times upper limit of normal (ULN) (5 times ULN if liver metastases are present)
• Albumin at least 2.8 g/dL
• Renal
• Creatinine less than 1.5 times ULN
• Other
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No active serious infection
• No other malignancy within the past 5 years except nonmelanoma skin cancer or carcinoma in situ of the cervix
• No overt psychosis or mental disability that would preclude informed consent
• No other life-threatening illness within the past 6 months
• PRIOR CONCURRENT THERAPY:
• Biologic therapy
• At least 3 months since prior autologous bone marrow or stem cell transplantation
• No concurrent biologic therapy
• Chemotherapy
• Recovered from prior systemic chemotherapy
• Prior topoisomerase I inhibitor therapy allowed
• No other concurrent chemotherapy
• Endocrine therapy
• Not specified
• Radiotherapy
• More than 4 weeks since prior cranial, spinal, or whole pelvis radiotherapy
• More than 4 weeks since prior radiotherapy to 25% of bone marrow reserve
• No concurrent radiotherapy
• Surgery
• At least 4 weeks since prior major surgery and recovered
• No concurrent surgery
• Other
• More than 28 days since prior investigational drugs (including analgesics or antiemetics)
• No more than 2 prior treatment regimens for this disease
• No other investigational drugs during and for 28 days after study therapy
• No other concurrent anticancer therapy
• No concurrent grapefruit or grapefruit juice