RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die.

PURPOSE: Phase II trial to study the effectiveness of temozolomide in treating adults with newly diagnosed primary malignant glioblastoma multiforme.

OBJECTIVES:

• Determine the antitumor activity of temozolomide in adults with newly diagnosed glioblastoma multiforme.
• Define the relationship between tumor O6-alkylguanine-DNA alkyltransferase activity and tumor response in these patients.
• Define the relationship between tumor DNA mismatch repair activity and tumor response to temozolomide.

OUTLINE: Patients receive temozolomide orally once daily on days 1-5. Treatment courses are repeated every 28 days. In the absence of disease progression and toxicity, patients receive up to 4 courses of treatment prior to radiation therapy. After radiation therapy, patients demonstrating partial or complete response may receive an additional 12 courses of treatment.

Patients are followed every 8-12 weeks for 2 years.

PROJECTED ACCRUAL: This study will accrue 50 patients.

DISEASE CHARACTERISTICS:

• Histologically proven, newly diagnosed, supratentorial malignant glioblastoma multiforme not requiring immediate radiation therapy
• At least 1 bidimensionally measurable lesion

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Karnofsky 70-100%

Life expectancy:

• Greater than 12 weeks

Hematopoietic:

• Absolute neutrophil count at least 1500/mm^3
• Platelet count at least 100,000/mm^3
• Hemoglobin at least 10 g/dL

Hepatic:

• Bilirubin less than 1.5 times upper limit of normal (ULN)
• SGOT and SGPT less than 2.5 times ULN
• Alkaline phosphatase less than 2 times ULN

Renal:

• BUN less than 1.5 times ULN
• Creatinine less than 1.5 times ULN

Other:

• Must be neurologically stable

• No systemic disease

• No acute infection requiring intravenous antibiotics

• No frequent vomiting

• No other medical condition that would interfere with oral medication intake such as partial bowel obstruction

• No prior or concurrent malignancies except:

  • Surgically cured carcinoma in situ of the cervix
  • Basal or squamous cell carcinoma of the skin

• HIV negative

• No AIDS-related illness

• Not pregnant or nursing

• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No prior biologic therapy
• No concurrent biologic therapy (growth factors or erythropoietin)

Chemotherapy:

• No prior chemotherapy
• No other concurrent chemotherapy

Endocrine therapy:

• Concurrent steroid allowed (must be on stable dose for at least 1 week prior to study)

Radiotherapy:

• No prior radiation therapy
• No prior interstitial brachytherapy
• No prior radiosurgery to the brain
• Not requiring immediate radiation therapy
• No concurrent radiotherapy

Surgery:

• Recovered from any effects of prior surgery
• At least 2 weeks since prior surgical resection

Other:

• No other concurrent investigational drugs