RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. O(6)-benzylguanine may increase the effectiveness of carmustine by making tumor cells more sensitive to the drug.

PURPOSE: Phase II trial to study the effectiveness of combining carmustine with O(6)-benzylguanine in treating patients who have newly diagnosed supratentorial glioblastoma multiforme.

OBJECTIVES:

• Determine the activity of carmustine and O6-benzylguanine in patients with newly diagnosed supratentorial glioblastoma multiforme not requiring immediate radiotherapy.
• Determine the toxicity of this regimen in these patients.

OUTLINE: Patients receive O6-benzylguanine IV over 1 hour followed approximately 1 hour later by carmustine IV over 1 hour on day 1. Treatment repeats every 6 weeks for a maximum of 3 courses in the absence of disease progression or unacceptable toxicity. Patients are then referred for radiotherapy. Patients who demonstrate tumor response after completion of the third course of chemotherapy receive 6 additional courses after completion of radiotherapy.

PROJECTED ACCRUAL: A total of 19-36 patients will be accrued for this study.

DISEASE CHARACTERISTICS:

• Histologically confirmed newly diagnosed supratentorial glioblastoma multiforme not requiring immediate radiotherapy
• Measurable residual disease on a contrast-enhanced MRI or CT scan (for patients with a medical contraindication for MRI) with a baseline scan obtained at the corticosteroid dose the patient is receiving on the day of treatment

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• Karnofsky 60-100%

Life expectancy

• Not specified

Hematopoietic

• Absolute granulocyte count at least 1,500/mm3
• Platelet count at least 100,000/mm3
• Hemoglobin greater than 10 g/dL

Hepatic

• Bilirubin normal
• SGOT no greater than 2.5 times upper limit of normal

Renal

• Creatinine no greater than 1.5 mg/dL
• BUN no greater than 25 mg/dL

Pulmonary

• DLCO greater than 75% predicted

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 2 months after study

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• Not specified

Endocrine therapy

• See Disease Characteristics
• Concurrent corticosteroids allowed if on stable dose for 3 days before study

Radiotherapy

• See Disease Characteristics

Surgery

• No more than 28 days since prior surgical resection or biopsy