Fludarabine Followed by Alemtuzumab in Treating Patients With Chronic Lymphocytic Leukemia

1. Specific Diagnosis of B-Cell CLL 1.1 An absolute lymphocytosis of \> 5,000/µl 1.1.1 Morphologically, the lymphocytes must appear mature with \< 55% prolymphocytes. 1.1.2 Bone marrow examination must include at least a unilateral aspirate and biopsy. The aspirate smear must show \> 30% of all nucleated cells to be lymphoid or the bone marrow core biopsy must show lymphoid infiltrates compatible with marrow involvement by CLL. The overall cellularity must be normocellular or hypercellular. 1.1.3 Local institution lymphocyte phenotype must reveal a predominant B-cell monoclonal population sharing a B-cell marker (CD19, CD20, CD23, CD24) with the CD5 antigen, in the absence of other pan-T-cell markers. Additionally, the B-cells must be monoclonal with regard to expression of either κ or λ and have surface immunoglobulin expression of low density. Patients with bright surface immunoglobulin levels must have CD23 co-expression. 1.2 Staging 1.2.1 Patients must be in the intermediate- or high-risk categories of the modified three-stage Rai staging system (i.e., stages I, II, III, or IV) per the protocol. 1.2.2 Patients in the intermediate-risk group must have evidence of active disease as demonstrated by at least one of the following criteria: * Massive or progressive splenomegaly and/or lymphadenopathy * Presence of weight loss \> 10% over the preceding 6 month period; * Grade 2 or 3 fatigue * Fevers \> 100.5°C or night sweats for greater than 2 weeks without evidence of infection * Progressive lymphocytosis with an increase of \> 50% over a 2 month period or an anticipated doubling time of less than 6 months. 2. Prior Treatment: No prior therapy for CLL including corticosteroids for autoimmune complications that have developed since the initial diagnosis of CLL. 3. No medical condition requiring chronic use of oral corticosteroids. 4. Age ≥18 years. 5. Performance Status 0 - 2. 6. No HIV disease. Due to alterations in host immunity, patients with HIV may not be enrolled. 7. Non-pregnant and non-nursing. Due to the unknown teratogenic potential of Campath-1H, pregnant or nursing women may not be enrolled. Women and men of reproductive potential should agree to use an effective means of birth control. 8. Initial Required Laboratory Values: Creatinine \<1.5 x upper limit of institutional normal value Coomb's Testing NEGATIVE