Inclusion Criteria:

1. Patients with CLL or SLL as defined by the WHO classification system with indications
for treatment by National Cancer Institute (NCI) Working Group criteria.

2. Measurable disease (lymphocytes equal or greater than 5,000/µL, or measurable
lymphadenopathy, or bone marrow involvement greater than 30%).

3. Males and females 18 years of age or older.

4. Patients must be relapsed or refractory and have been treated with a minimum of one
prior purine analog-based chemotherapy regimen (e.g., fludarabine, cladribine, or
pentostatin).

5. All previous cancer therapies, radiation, hormonal therapy and surgery, must have
been discontinued at least 28 days prior to the start of treatment. Any cytotoxic
chemotherapy must have been discontinued 28 days prior to the start of treatment.
Acute toxicities from prior therapy must have resolved to Grade ≤ 1 above baseline.

6. Normal oxygen saturation with pulse oximetry on room air.

7. Hemoglobin 9 or greater gm/dL (may be post-transfusion).

8. Platelet count 50 x103/mL or greater

9. Total bilirubin less than 2 X ULN, and ALT and AST less than 2 x ULN.

10. Serum creatinine 2 X ULN or less. In addition, the calculated glomerular filtration
rate (GFR) must be > 30cc/min.

11. ECOG Performance Status 2 or less.

12. Anticipated survival of at least 3 months.

13. For men and women of child-producing potential, use of effective contraceptive
methods during the study and for one month after discontinuation of treatment.

Exclusion Criteria:

1. Pregnant or lactating women.

2. Severe chronic obstructive pulmonary disease with hypoxemia or an uncorrectable
pulmonary compromise.

3. Seizures not controlled by anticonvulsant therapy.

4. Participation in any investigational drug study within 28 days before study entry.

5. Patients with second malignancy requiring active treatment.

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

7. Clinically significant bleeding event within the last 3 months, unrelated to trauma,
or underlying condition that would be expected to result in a bleeding diathesis.

8. Patients with life- or function-threatening CLL complications (e.g., cord
compression, hemolytic crisis, urinary tract obstruction).

9. Any illness or condition that in the opinion of the investigator may affect safety of
treatment or evaluation of any of the study's endpoints.

10. Systemic treatment for CLL/SLL within 28 days of study entry

11. Subjects with a history of leukemic meningitis, or signs and symptoms suggestive of
leukemic meningitis, must have a negative lumbar puncture within 2 weeks of study
entry.