Denileukin Diftitox in Treating Patients With Fludarabine-Refractory B-Cell Chronic Lymphocytic Leukemia

DISEASE CHARACTERISTICS: Diagnosis of B-cell chronic lymphocytic leukemia (CLL) meeting the following criteria at any time during the course of disease (e.g., at initial diagnosis or relapse): Absolute lymphocytosis > 5,000/mm^3 Lymphocytes must appear mature with < 55% prolymphocytes More than 30% of all nucleated cells are lymphoid on bone marrow aspirate smear Lymphoid infiltrates compatible with bone marrow involvement by CLL on core bone marrow biopsy Predominant B-cell monoclonal population of cells share the B-cell marker (CD19) with the CD5 antigen in the absence of other pan-T-cell markers by lymphocyte immunophenotyping High-risk disease OR intermediate-risk disease Patients in the intermediate-risk group must have evidence of active disease as demonstrated by at least 1 of the following criteria: Massive or progressive splenomegaly and/or adenopathy Weight loss > 10% within the past 6 months Common toxicity grade 2-4 fatigue Fevers > 100.5°F OR night sweats for more 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 < 6 months Failed at least 1 prior fludarabine regimen, as defined by 1 of the following criteria: Refractory or intolerant to fludarabine Relapsed within 6 months after completion of fludarabine No CNS leukemia No mantle cell lymphoma in leukemic phase PATIENT CHARACTERISTICS: Age 18 and over Performance status Zubrod 0-2 Life expectancy More than 2 months Hematopoietic Absolute neutrophil count ≥ 1,000/mm^3 Platelet count ≥ 50,000/mm^3 Hemoglobin ≥ 8 g/dL (transfusion allowed) Hepatic Albumin ≥ 3 g/dL AST and ALT ≤ 2.5 times upper limit of normal (ULN) Bilirubin ≤ 1.5 times ULN No hepatitis B or C infection Renal Creatinine ≤ 1.5 mg/dL OR Creatinine clearance ≥ 40 mL/min Cardiovascular LVEF ≥ 40% Other No uncontrolled infection No other concurrent serious illness No HIV infection Not pregnant or nursing Negative pregnancy test Fertile patients must use two effective methods of contraception (one must be non-hormonal) during and for at least 1 month after study participation PRIOR CONCURRENT THERAPY: Biologic therapy Prior denileukin diftitox allowed Chemotherapy See Disease Characteristics Endocrine therapy No concurrent corticosteroids as anti-emetics Radiotherapy No concurrent radiotherapy Surgery Not specified Other At least 28 days since prior anticancer therapy and recovered No other concurrent antineoplastic drugs