Inclusion Criteria:

- Diagnosis of CLL as defined by the NCI-working group

- Previous treatment with standard systemic chemotherapy or immunotherapy.

- Disease progression or relapse after treatment.

- Indication for treatment as defined by the NCI Working Group Guidelines (Cheson,
1996)

- ECOG performance status ≤ 2

- Adequate liver and renal and bone marrow function

Exclusion Criteria:

- Treatment of CLL with chemotherapy, monoclonal antibody or radiotherapy within 60
days prior to entering the study. Acute toxicities from prior therapy must have
resolved to Grade ≤ 1.

- Class 3 or 4 cardiac disease as defined by the New York Heart Association Functional
Classification

- Severe or debilitating pulmonary disease (dyspnea at rest, significant shortness of
breath, COPD)

- Active secondary malignancy or history of other malignancy within the last five years

- Active symptomatic fungal, bacterial and/or viral infection including active HIV or
viral hepatitis (A, B or C).

- Patients who are contraindicated for treatment with rituximab

- Diagnosis of prolymphocytic leukemia, hairy cell leukemia, leukemic phase of
non-Hodgkin's lymphoma, or other non-B-CLL B-cell malignancy;

- T-CLL or other T-cell malignancy