Inclusion Criteria:

- Histologically or cytologically confirmed CLL or SLL.

- Age ≥ 65

- CLL - Binet Stage C or Rai stage III or IV or has active disease defined by meeting
at least one of the following criteria:

- Evidence of progressive marrow failure as manifested by the development of, or
worsening of, anemia and/or thrombocytopenia

- Massive (i.e., >6 cm below the left costal margin) or progressive or symptomatic
splenomegaly

- Massive nodes (i.e., > 10 cm in longest diameter) or progressive or symptomatic
lymphadenopathy

- Progressive lymphocytosis with an increase of more than 50% over a 2-month
period or lymphocyte doubling time of less than 6 months

- Autoimmune anemia and/or thrombocytopenia poorly responsive to corticosteroids
or other standard therapy

- At least one of the following disease-related symptoms:

- Unintentional weight loss ≥10% within the previous 6 months

- Significant fatigue

- Fevers >100.4F for ≥2 weeks without other evidence of infection

- Night sweats for ≥1 month without evidence of infection

- SLL - has active disease as defined above for CLL, except the lymphocytosis criterion
does not apply

- World Health Organization (WHO) Performance Status of ≤2

- For men of child-bearing potential, willing to use adequate methods of contraception
for the entire duration of the study

- Able to provide written informed consent

Exclusion Criteria:

- Prior therapy for CLL or SLL, except corticosteroids for symptom relief

- Treatment with a short course of corticosteroids for symptom relief within 1-week
prior to Visit 1

- Known active central nervous system involvement of the malignancy

- Ongoing active, serious infection requiring systemic therapy. Patients may be
receiving prophylactic antibiotics and antiviral therapy at the discretion of the
treating physician.

Serum creatinine ≥2.0 mg/dL

- Serum bilirubin ≥2 mg/dL (unless due to Gilbert's syndrome) or serum transaminases
(i.e., aspartate aminotransferase [AST], alanine aminotransferase [ALT]) ≥2 x upper
limit of normal

- Positive test for human immunodeficiency virus (HIV) antibodies

- Active hepatitis B or C (confirmed by ribonucleic acid [RNA] test). Patients with
serologic evidence of prior exposure are eligible.