RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Colony-stimulating factors such as filgrastim may increase the number of immune cells found in bone marrow or peripheral blood and may help a person's immune system recover from the side effects of chemotherapy.

PURPOSE: Phase II trial to study the effectiveness of combining carboplatin, temozolomide, and filgrastim in treating patients who have newly diagnosed or recurrent high-grade glioma.

OBJECTIVES:

• Determine the response rate in patients with newly diagnosed high-grade glioma treated with temozolomide, carboplatin, and filgrastim (G-CSF).
• Determine the toxicity of this treatment regimen in these patients.
• Determine the rate of tumor progression in patients treated with this regimen.

OUTLINE: This is a multicenter study. Patients are stratified according to disease category (glioblastoma multiforme vs anaplastic astrocytoma vs several other high-grade mixed gliomas).

Patients receive carboplatin IV over 4 hours on days 1-2; oral temozolomide every 12 hours on days 1-5; and filgrastim (G-CSF) subcutaneously or IV daily starting no earlier than day 7 and continuing until blood counts recover. Treatment repeats every 28 days for at least 4 courses in the absence of disease progression or unacceptable toxicity.

PROJECTED ACCRUAL: A total of 102-222 (17-37 per each of 6 strata) will be accrued for this study within 4 years.

• Biological: filgrastim
• Drug: carboplatin
• Drug: temozolomide

DISEASE CHARACTERISTICS:

• Histologically confirmed newly diagnosed glioblastoma multiforme or anaplastic astrocytoma

  • Residual tumor on postoperative MRI
• Bidimensionally measurable disease

PATIENT CHARACTERISTICS:

Age:

• Under 65

Performance status:

• Karnofsky or Lansky 70-100% OR
• ECOG 0-2

Life expectancy:

• Not specified

Hematopoietic:

• Absolute neutrophil count at least 1,000/mm^3
• Hemoglobin at least 8 g/dL (transfusion allowed)
• Platelet count greater than 100,000/mm^3

Hepatic:

• Bilirubin less than 1.5 times upper limit of normal (ULN)
• SGPT no greater than 3 times ULN

Renal:

• Age 5 years and under: Creatinine less than 1.2 mg/dL
• Age over 5 to 10 years: Creatinine less than 1.5 mg/dL
• Age over 10 to 15 years: Creatinine less than 1.8 mg/dL
• Age over 15 years: Creatinine less than 2.4 mg/dL

Cardiovascular:

• No myocardial infarction within the past 6 months

Other:

• No other concurrent serious medical condition that would preclude study
• Able to tolerate oral medications
• No prior malignancy for which patient received prior chemotherapy or spinal irradiation
• No history of severe allergic reaction to platinum-containing compounds
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• At least 72 hours since prior filgrastim (G-CSF)

Chemotherapy:

• No prior chemotherapy
• No other concurrent chemotherapy

Endocrine therapy:

• Concurrent steroids for tumor-related cerebral edema allowed
• No concurrent corticosteroids for solely antiemetic purposes

Radiotherapy:

• No prior or concurrent radiotherapy

Surgery:

• Recovered from prior surgery
• No concurrent surgery