DISEASE CHARACTERISTICS:

• Histologically confirmed recurrent or refractory sarcomas, including the following:

  • Rhabdomyosarcoma
  • Nonrhabdomyosarcomatous soft tissue sarcoma
  • Ewing's sarcoma

• Measurable disease by imaging studies

  • Lesions assessable only by radionuclide scans are not considered measurable
  • If the only measurable lesion has been previously irradiated, then that lesion must have shown evidence of an interim increase in size

• No significant amount of metastatic liver disease, defined as the following:

  • Lesions occupying more than 25% of the liver by imaging and abnormal liver function tests or abnormal synthetic liver function

PATIENT CHARACTERISTICS:

Age

• 21 and under (at time of diagnosis)

Performance status

• Lansky 50-100% (10 years of age and under)
• Karnofsky 50-100% (over 10 years of age)

Life expectancy

• Not specified

Hematopoietic

• Absolute neutrophil count at least 1,000/mm^3
• Platelet count at least 100,000/mm^3 (transfusion independent)
• Hemoglobin at least 8.0 g/dL (transfusion allowed)

Hepatic

• See Disease Characteristics
• Bilirubin no greater than upper limit of normal (ULN)
• Total alkaline phosphatase no greater than ULN OR
• Hepatic fraction alkaline phosphatase and 5 nucleotidase no greater than ULN
• SGOT and SGPT normal for age
• Albumin at least 2.5 g/dL

Renal

• Maximum creatinine based on age as follows:

  • 0.8 mg/dL (5 years of age and under)
  • 1.0 mg/dL (6 to 10 years of age)
  • 1.2 mg/dL (11 to 15 years of age)
  • 1.5 mg/dL (over 15 years of age) OR
• Creatinine clearance or radioisotope glomerular filtration rate (GFR) at least 70 mL/min

Cardiovascular

• No uncompensated congestive heart failure within the past 6 months

Other

• Not pregnant or nursing
• Fertile patients must use effective contraception during and for 2 months after study participation
• No active uncontrolled infection
• Weight ≥ 15 kilograms

PRIOR CONCURRENT THERAPY:

Biologic therapy

• More than 1 week since prior growth factors that support platelet or white blood cell number or function
• At least 7 days since prior biologic agents and recovered
• No prior allogeneic stem cell transplantation
• No other concurrent immunomodulating agents

Chemotherapy

• More than 3 weeks since prior myelosuppressive chemotherapy (4 weeks for nitrosoureas) and recovered
• No more than 2 prior multi-agent chemotherapy regimens
• No other concurrent anticancer chemotherapy

Endocrine therapy

• Concurrent steroids allowed

Radiotherapy

• See Disease Characteristics
• At least 6 weeks since prior since prior extended radiotherapy and recovered
• No prior total body radiotherapy
• Concurrent radiotherapy to localized painful lesions allowed provided at least 1 measurable lesion is not irradiated* NOTE: *Any irradiated lesion cannot be used to assess tumor response

Surgery

• Not specified

Other

• At least 7 days since prior enzyme-inducing anticonvulsants (e.g., carbamazepine, phenobarbital, or phenytoin)
• No concurrent enzyme-inducing anticonvulsants
• No other concurrent investigational agents

• No concurrent CYP3A4 inhibitors, including the following:

  • Grapefruit juice
  • Erythromycin
  • Azithromycin
  • Clarithromycin
  • Rifampin and its analogs
  • Fluconazole
  • Ketoconazole
  • Itraconazole
  • Cimetidine
  • Cannabinoids (marijuana or dronabinol)
  • Leukotriene inhibitors used in asthma (e.g., zafirlukast, montelukast, or zileuton)