Inclusion Criteria:

• Patients must have a confirmed diagnosis of CLL or small lymphocytic lymphoma (SLL) based upon the Revised NCI-sponsored Working Group guidelines for CLL;
• Relapsed or refractory disease after previous chemotherapy treatment;
• Age > 18 years;
• Adequate renal function with creatinine <= 1.5 mg/dL;
• Adequate liver function with alkaline phosphatase <= 2.5 X upper limit of normal, serum glutamic oxaloacetic transaminase (SGOT), and serum glutamic pyruvic transaminase (SGPT) <= 2.5 X upper limit of normal; and total bilirubin <= 2.0 X upper limit of normal;
• Adequate bone marrow function as determined by having platelets > 50,000/mm3 without transfusion in the preceding 2 weeks and an absolute neutrophil count (ANC) => 1,500 cells/mm3 without growth factor support; unless cytopenias due to marrow infiltration;
• Able to give informed consent;
• A minimum of 4 weeks must have elapsed from the completion of any previous treatment regimen, including radiation and biologic therapies (6 weeks if a prior nitrosourea or mitomycin C, 12 weeks if radioimmunotherapy) to treatment on Day 1 Cycle 1. Patients must have recovery from treatment-associated toxicity(ies);
• A predicted life expectancy of at least 6 months; and
• Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2.

Exclusion Criteria:

• More than three systemic treatment regimens for CLL/SLL (excluding immunotherapies and biologic therapies);
• Concurrent malignancy that the patient has not been free of for at least 5 years, excluding curatively treated carcinoma-in-situ or non-melanoma skin cancer;
• Any pregnant or lactating females. Females of childbearing potential must have a negative pregnancy test and all male and female patients of reproductive potential must agree to use adequate birth control;
• Known HIV-positive patients;
• Any underlying medical conditions or circumstances that would contraindicate therapy with study treatment, affect compliance or impair evaluation of study endpoints;
• Receiving investigational agents within 4 weeks of the study treatment; and
• Known allergy to reagents in the study.