Inclusion Criteria:

1. Male or female, 18 years old or older.

2. A diagnosis of Chronic Lymphocytic Leukemia(CLL) which is CD5/CD19/CD23 positive,
confirmed by peripheral blood immunophenotyping and/or lymph node biopsy and
immunophenotyping and/or bone marrow biopsy and immunophenotyping. CD23-negative CLL
cases are eligible, however additional diagnostic confirmation should include absence
of Cyclin D1 rearrangement [t(11;14)] as determined by standard laboratory methods
(such as fluorescent in situ hybridization).

3. Patients are planning to start chemotherapy for CLL recommended and prescribed by
their primary oncologist.

4. Peripheral blood lymphocyte count above 20,000/mm3

5. Be able to provide written informed consent

Exclusion Criteria

1. Patients who have had chemotherapy or radiotherapy within 4 weeks (6 weeks for
nitrosoureas or mitomycin C) prior to entering the study or those who have not
recovered from adverse events due to agents administered more than 4 weeks earlier.

2. Patients who are receiving any other investigational agents.

3. History of allergic reactions attributed to compounds of similar chemical or biologic
composition to vincristine.

4. Uncontrolled concurrent illness including, but not limited to, ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia, or psychiatric illness/social situations that would limit compliance with
study requirements.

5. Liver function test abnormalities of ≥ grade 3 (total bilirubin >3 ULN (upper limit
of normal), AST> 5 ULN, ALT> 5 ULN) as per CTCAE 4.0 criteria, or direct bilirubin ≥
3.0 mg/dL

6. Pre-existing neuropathy grade 2 or greater as per CTCAE 4.0 criteria (moderate
symptoms limiting instrumental activities of daily living - ADLs)

7. Patients who are pregnant or planning to become pregnant during their participation
in the study.