RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining chemotherapy with peripheral stem cell transplantation may allow the doctor to give higher doses of chemotherapy drugs and kill more tumor cells.

PURPOSE: This phase I/II trial is studying the side effects and best dose of temozolomide when given with peripheral stem cell transplantation and to see how well they work in treating children with newly diagnosed malignant glioma or recurrent CNS tumors or other solid tumors.

OBJECTIVES:

• Determine the maximum tolerated dose of temozolomide in children with newly diagnosed malignant glioma or recurrent CNS or other solid tumors.
• Evaluate the toxicity of this treatment in these patients.
• Determine the activity of this treatment in these patients.

OUTLINE: This is a dose escalation study of temozolomide.

Patients receive filgrastim (G-CSF) subcutaneously (SQ) or IV beginning on day -5 and continuing through at least day 3. Peripheral blood stem cells (PBSC) are collected on days 0, 2, and 4. Patients then receive oral temozolomide daily for 5 consecutive days. PBSC collections are reinfused 1 day after the last dose of temozolomide. Patients also receive G-CSF beginning at the time of transplant and continuing until blood counts recover. Treatment continues in the absence of disease progression or unacceptable toxicity.

Cohorts of 3-6 patients receive escalating doses of temozolomide until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose at which 2 of 6 patients experience dose limiting toxicities.

Patients are followed every 3 months for 1-3 years, then annually thereafter.

PROJECTED ACCRUAL: A total of 30 patients will be accrued for this study over 12 months.

DISEASE CHARACTERISTICS:

• Histologically confirmed newly diagnosed malignant glioma or recurrent malignant CNS tumor of any pathology OR

• Histologically confirmed non-CNS tumor

  • Recurrent soft tissue sarcomas (e.g., rhabdomyosarcoma)
  • Recurrent or resistant neuroblastoma
  • Recurrent Wilm's tumor
  • Recurrent Ewing's sarcoma
  • Recurrent primitive neuroectodermal tumors
  • Recurrent nasopharyngeal carcinoma
  • Recurrent germ cell tumor

• Expected cure rate less than 10% with standard therapy

• Measurable and/or active disease

• History of bone marrow tumor infiltration with or without mass lesions or isolated abnormal CSF cytology as only evidence of recurrent disease allowed if complete response was first achieved with primary conventional therapy

PATIENT CHARACTERISTICS:

Age:

• 18 and under

Performance status:

• Karnofsky 70-100% OR
• Lansky 70-100%

Life expectancy:

• Greater than 8 weeks

Hematopoietic:

• Reasonably cellular bone marrow (greater than 15% cellularity on biopsy)
• Absolute neutrophil count greater than 1,000/mm^3
• Platelet count greater than 75,000/mm^3

Hepatic:

• Bilirubin less than 2.0 mg/dL
• SGPT less than 120 U/L

Renal:

• Creatinine less than 1.5 mg/dL

Cardiovascular:

• Systolic fraction or ejection fraction at least 80% predicted for age by echocardiogram

Pulmonary:

• CVC or DLCO at least 60% predicted for age OR clearance from pulmonologist

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• HIV negative
• No active infection
• Able to tolerate vigorous hydration schedule

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No concurrent white blood cell transfusion
• No other concurrent hematopoietic growth factors

Chemotherapy:

• See Disease Characteristics
• At least 4 weeks since prior chemotherapy
• No other concurrent cytotoxic drugs (systemic or intrathecal)

Endocrine therapy:

• Concurrent corticosteroids allowed

Radiotherapy:

• See Disease Characteristics
• At least 1 week since prior radiotherapy

Surgery:

• At least 1 week since prior surgery

Other:

• No other concurrent investigational agents