Inclusion Criteria:

   1. Males or females of 65 years of age or greater. Patients between the ages of 65 and 70
   years of age must have 1 or more of the following comorbidities that may preclude the
   use of frontline chemo-immunotherapy with fludarabine, cyclophosphamide, or rituximab:

      - creatinine clearance < 70 mL/min using the Cockcroft-Gault equation

      - platelet count < 100,000/μL or hemoglobin < 10 g/dL

      - clinically apparent autoimmune cytopenia (autoimmune hemolytic anemia or immune
      thrombocytopenia)

      - ECOG performance score = 1 or 2

   2. Diagnosis of CLL/SLL that meets IWCLL diagnostic criteria (Hallek 2008)

   3. Active disease meeting at least 1 of the following IWCLL criteria (Hallek 2008) for
   requiring treatment:

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

      - Massive nodes or progressive or symptomatic lymphadenopathy

      - Progressive lymphocytosis

      - Autoimmune hemolytic anemia and/or immune thrombocytopenia that is poorly
      responsive to corticosteroids or standard therapy

      - Constitutional symptoms

   4. Measurable nodal disease by computed tomography (CT)

   5. ECOG performance status of 0-2

   6. Life expectancy > 4 months from randomization

   7. Adequate hematologic function, defined as absolute neutrophil count (ANC) ≥ 1,000/μL
   (independent of growth factor support for at least 7 days prior to screening) and
   platelet count ≥ 50,000/μL (independent of transfusion and growth factor support for
   at least 7 days prior to screening)

   8. Adequate hepatic function, defined as serum aspartate transaminase (AST) and alanine
   transaminase (ALT) < 2.5 x upper limit of normal (ULN), and total bilirubin ≤ 1.5 x
   ULN

   9. Adequate renal function, defined as estimated creatinine clearance ≥ 30 mL/min using
   the Cockcroft-Gault equation

10. Willingness to receive all outpatient treatment, all laboratory monitoring, and all
   radiological evaluations at the institution that administers study drug for the entire
   study

11. Willingness of male patients, if sexually active with a female of childbearing
   potential, to use an effective barrier method of contraception during the study and
   for 3 months following the last dose of study drug

12. Ability to provide written informed consent and to understand and comply with the
   requirements of the study

Exclusion Criteria:

   1. Known involvement of the central nervous system by lymphoma or leukemia

   2. History or current evidence of Richter's transformation or prolymphocytic leukemia

   3. Documentation of deletion of the short arm of chromosome 17: del(17p13.1) in more than
   20% of cells examined on any pretreatment fluorescence in situ hybridization (FISH) or
   cytogenetic evaluation

   4. Uncontrolled autoimmune hemolytic anemia or idiopathic thrombocytopenic purpura

   5. Any previous treatment (chemotherapy, radiotherapy, and/or monoclonal antibodies)
   intended specifically to treat CLL/SLL

   6. Received any immunotherapy, vaccine, or investigational drug within 4 weeks prior to
   randomization

   7. Corticosteroid use within 1 week prior to first dose of study drug, with the exception
   of inhaled, topical, or other local administrations. Patients requiring systemic
   steroids at daily doses > 20 mg prednisone (or corticosteroid equivalent, see Appendix
   N), or those who are administered steroids for leukemia control or white blood cell
   (WBC)-count-lowering are excluded.

   8. Major surgery within 4 weeks prior to randomization

   9. History of prior malignancy, with the exception of the following:

      - malignancy treated with curative intent and with no evidence of active disease
      present for more than 3 years prior to screening and felt to be at low risk for
      recurrence by treating physician

      - adequately treated nonmelanomatous skin cancer or lentigo maligna melanoma
      without current evidence of disease

      - adequately treated cervical carcinoma in situ without current evidence of disease

10. Currently active, clinically significant cardiovascular disease or a history of
   myocardial infarction within 6 months prior to randomization

11. Inability to swallow capsules or tablets, or disease significantly affecting
   gastrointestinal function

12. Uncontrolled active systemic fungal, bacterial, viral, or other infection or
   requirement for intravenous (IV) antibiotics

13. Known history of infection with human immunodeficiency virus (HIV)

14. Serologic status reflecting active hepatitis B or C infection

15. History of stroke or intracranial hemorrhage within 6 months prior to enrollment

16. Current life-threatening illness, medical condition, or organ-system dysfunction that
   could compromise patient safety or put the study at risk

17. Requirement for anticoagulation with warfarin

18. Requirement for treatment with a strong CYP3A4/5 and/or CYP2D6 inhibitor