RATIONALE: Drugs used in chemotherapy use different ways to stop cancer cells from dividing so they stop growing or die. Monoclonal antibodies such as alemtuzumab can locate cancer cells and either kill them or deliver cancer-killing substances to them without harming normal cells.

PURPOSE: Phase II trial to study the effectiveness of fludarabine followed by alemtuzumab in treating patients who have chronic lymphocytic leukemia.

OBJECTIVES: I. Determine the overall response rate of previously untreated patients with stage I, II, III, or IV B-cell chronic lymphocytic leukemia when treated with fludarabine induction followed by alemtuzumab consolidation. II. Determine the infectious toxic effects and feasibility of this regimen in this patient population. III. Determine the treatment-related toxic effects, including infection and injection site reactions, of subcutaneous vs intravenous alemtuzumab in patients treated with this regimen. IV. Determine the progression-free and overall survival of patients treated with this regimen. V. Determine the immunologic effects of this regimen in these patients.

OUTLINE: Patients receive fludarabine IV over 30 minutes 5 days a week. Treatment repeats every 28 days for 4 courses in the absence of disease progression. Patients undergo clinical staging after completion of course 4 of fludarabine followed by 2 months of observation. Patients with stable or responding disease receive alemtuzumab subcutaneously 3 days a week for 6 weeks. Patients undergo clinical staging again after completion of 6 weeks of alemtuzumab followed by 2 more months of observation. Patients are followed every 3 months for 1 year and then every 6 months for 8 years.

PROJECTED ACCRUAL: A maximum of 50 patients will be accrued for this study within 1 year.

• Biological: alemtuzumab
• Drug: fludarabine phosphate

• Byrd JC, Byrd JC, Peterson BL, Rai KR, Byrd JC, Peterson BL, Rai KR, Hurd D, Hohl R, Perry MC, Gockerman J, Nattam S, Larson RA. Fludarabine followed by alemtuzumab consolidation for previously untreated chronic lymphocytic leukemia: final report of Cancer and Leukemia Group B study 19901. Leuk Lymphoma. 2009 Oct;50(10):1589-96.
• Rai KR, Freter CE, Mercier RJ, Cooper MR, Mitchell BS, Stadtmauer EA, Santabarbara P, Wacker B, Brettman L. Alemtuzumab in previously treated chronic lymphocytic leukemia patients who also had received fludarabine. J Clin Oncol. 2002 Sep 15;20(18):3891-7.

DISEASE CHARACTERISTICS: Previously untreated, stage I, II, III, or IV B-cell chronic lymphocytic leukemia (CLL) Lymphocytosis greater than 5,000/mm3 with less than 55% prolymphocytes Bone marrow aspirate with greater than 30% of all nucleated cells being lymphoid OR Bone marrow core biopsy must show lymphoid infiltrates compatible with marrow involvement by CLL Overall cellularity must be normocellular or hypercellular Monoclonal B-cell population positive for at least 1 B-lineage marker (CD19, CD20, CD23, CD24) with coexpression of CD5 Bright surface immunoglobulin levels must have CD23 coexpression Stage I or II disease must have evidence of active disease demonstrated by at least 1 of the following: Massive or progressive splenomegaly and/or lymphadenopathy Presence of weight loss greater than 10% over the preceding 6-month period Grade 2 or 3 fatigue Fevers greater than 100.5 degrees Fahrenheit or night sweats for greater than 2 weeks without evidence of infection Progressive lymphocytosis with an increase of greater than 50% over a 2-month period or an anticipated doubling time of less than 6 months

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: 0-2 Life expectancy: Not specified Hematopoietic: Direct Coomb's test negative Hepatic: Not specified Renal: Creatinine no greater than 1.5 times upper limit of normal Other: Not pregnant or nursing Fertile patients must use effective contraception No medical condition requiring chronic oral corticosteroids

PRIOR CONCURRENT THERAPY: Biologic therapy: No prior biologic therapy for CLL No concurrent epoetin alfa Chemotherapy: No prior chemotherapy for CLL No other concurrent chemotherapy Endocrine therapy: No prior corticosteroids for autoimmune complications that have developed since initial diagnosis of CLL No concurrent hormones except steroids for new adrenal failure or nondisease-related conditions (e.g., insulin for diabetes) No concurrent dexamethasone or other corticosteroid-based antiemetics Radiotherapy: No concurrent palliative radiotherapy Surgery: Not specified