DISEASE CHARACTERISTICS:

• Diagnosis of relapsed or refractory chronic lymphocytic leukemia (CLL) requiring therapy

  • Primary resistance, defined as disease progression without response during at least 2 courses of myelosuppressive therapy OR
  • Relapsed disease, defined as a response (remission or plateau) followed by relapse on or off prior therapy
  • At least 1 prior regimen must have contained fludarabine

• Intermediate or high-risk CLL

  • Intermediate-risk disease must satisfy at least 1 of the following criteria for active disease:

    • Massive or progressive splenomegaly and/or lymphadenopathy

      • Spleen tip greater than 6 cm below costal margin
    • More than 10% weight loss within the past 6 months
    • Grade 2 or 3 fatigue
    • Fevers greater than 100.5 degrees F or night sweats for more than 2 weeks without evidence of infection
    • Progressive lymphocytosis with an increase of more than 50% over a 2-month period or an anticipated doubling time of less than 6 months
    • Worsening anemia or thrombocytopenia

• Measurable disease with all of the following:

  • Absolute lymphocytosis greater than 5,000/mm^3
  • Lymphocytosis of small to moderate-size lymphocytes with less than 55% prolymphocytes, atypical lymphocytes, or lymphoblasts morphologically determined by manual differential
  • Bone marrow aspirate smear with at least 30% nucleated cells that are lymphoid or a bone marrow core biopsy showing lymphoid infiltrates compatible with CLL
  • Normocellular or hypercellular bone marrow
  • Lymphocyte immunophenotype that shows a predominant B-cell monoclonal population
• No Rai stage 0 CLL or stable CLL not requiring therapy
• No secondary leukemia or history of antecedent hematologic disorder prior to initial onset of CLL (e.g., myelodysplasia)

PATIENT CHARACTERISTICS:

Age:

• Over 18

Performance status:

• ECOG 0-2

Life expectancy:

• Not specified

Hematopoietic:

• See Disease Characteristics
• Platelet count at least 50,000/mm^3 (hematopoietic growth factor or transfusion independent)
• Negative Coombs' test
• No bleeding or coagulation disorder
• No history of hemolytic anemia, including autoimmune hemolytic anemia
• No history of autoimmune thrombocytopenia

Hepatic:

• Albumin at least 3.0 g/dL
• Bilirubin no greater than 2 mg/dL
• AST no greater than 1.5 times upper limit of normal (ULN) (5 times ULN if due to CLL)
• PT no greater than 1.5 times ULN OR
• INR no greater than 1.3
• PTT no greater than 1.5 times ULN
• No chronic hepatitis or cirrhosis

Renal:

• Creatinine no greater than 2.0 mg/dL

Cardiovascular:

• No uncontrolled congestive heart failure
• No active symptoms of coronary artery disease (i.e., uncontrolled arrhythmia or recurrent chest pain despite prophylactic medication)
• No New York Heart Association class III or IV disease
• No cardiovascular signs or symptoms grade 2 or greater

Other:

• Able to maintain an ambulatory infusion pump
• HIV negative
• No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix
• No known hypersensitivity to phosphorothioate-containing oligonucleotides, fludarabine, or cyclophosphamide
• No concurrent medical disease that would preclude study participation
• No uncontrolled seizure disorder
• No unresolved serious infection
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No prior autologous or allogeneic stem cell transplantation
• At least 3 weeks since prior immunologic therapy, cytokine therapy, vaccine therapy, or other biologic therapy for CLL and recovered
• No concurrent interleukin-11

Chemotherapy:

• See Disease Characteristics
• At least 3 weeks since prior chemotherapy and recovered

Endocrine therapy:

• No concurrent corticosteroid therapy

Radiotherapy:

• At least 3 weeks since prior radiotherapy for CLL and recovered

Surgery:

• No prior organ allograft
• At least 3 weeks since prior major surgery for CLL and recovered

Other:

• At least 3 weeks since other prior therapy for CLL and recovered
• No other concurrent investigational therapy
• No concurrent therapeutic anticoagulation
• No concurrent immunosuppressive drugs