Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically or cytologically proven recurrent or refractory solid tumors

- No leukemia

- Patients with brain tumors are not eligible until the first 2 patients at each dose
level are evaluable for toxicity

PATIENT CHARACTERISTICS:

- Age: 21 and under

- Performance status: Karnofsky 50-100% Lansky play scale 50-100% (for infants)

- Life expectancy: At least 8 weeks

- Absolute neutrophil count at least 1,000/mm3

- Hemoglobin at least 9 g/dL

- Platelet count at least 75,000/mm3

- Bilirubin less than 1.5 mg/dL

- SGPT less than 5 times upper limit of normal

- Creatinine normal for age OR GFR at least 70 mL/min

- Cardiac shortening fraction at least 27% OR institutional normal OR cardiac ejection
fraction greater than 50% OR institutional normal

- Neurologic deficits in patients with CNS tumors must be stable for at least 2 weeks

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception during and for 6 months after the
study

- No uncontrolled infection

PRIOR CONCURRENT THERAPY:

- At least 1 week since prior growth factor therapy and recovered

- At least 6 months since prior bone marrow transplantation and no evidence of graft
versus host disease

- At least 2 weeks since prior myelosuppressive chemotherapy and recovered

- At least 6 weeks since prior nitrosourea and recovered

- At least 2 weeks on stable dexamethasone for patients with CNS tumors

- No concurrent chemotherapy

- At least 2 weeks since prior palliative radiotherapy (small port)

- At least 6 months since prior substantial bone marrow radiation

- At least 6 months since total abdominal, pelvic, chest, mantle, and Y ports
radiotherapy

- No other concurrent anticancer therapy or investigational agents