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

PURPOSE: Phase II trial to study the effectiveness of theophylline in treating patients who have in situ, stage I, or stage II chronic lymphocytic leukemia.

OBJECTIVES: I. Determine the response rate in asymptomatic patients with stage 0, I, or II B-cell chronic lymphocytic leukemia treated with theophylline. II. Determine the toxicity of this treatment in these patients.

OUTLINE: Patients receive oral theophylline daily. Daily treatment continues for a maximum of 6 months in the absence of disease progression or unacceptable toxicity. Patients are followed every 4 months for 1 year.

PROJECTED ACCRUAL: A total of 35 patients will be accrued for this study over approximately 10 months.

DISEASE CHARACTERISTICS: Histologically proven stage 0, I, or II B-cell chronic lymphocytic leukemia Stable disease that would otherwise be observed

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 1 year Hematopoietic: Absolute lymphocyte count greater than 5,000/mm3 Mature lymphocytes with less than 55% prolymphocytes, atypical lymphocytes, or lymphoblasts Bone marrow with at least 30% lymphocytes Hepatic: No cirrhosis Renal: Not specified Cardiovascular: No history of unstable cardiac arrhythmia No active congestive heart failure Other: No history of uncontrolled seizure disorder Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No other concurrent condition that would make life expectancy less than 1 year

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent interferon alfa Chemotherapy: No prior chemotherapy No concurrent chemotherapy Endocrine therapy: At least 3 months since prior corticosteroids No concurrent corticosteroids Radiotherapy: Not specified Surgery: Not specified