2CDA With Rituximab in Hairy Cell Leukemia

Cladribine is a chemotherapy drug that has been used for over 10 years to treat HCL with very
good results and very low rate of side effects. Rituximab is an antibody protein that targets
a specific molecule on the surface of cancer cells in order to eliminate them. It has been
used for over 5 years to treat a number of cancers of blood and lymph nodes and has been used
with some success to treat patients with HCL whose disease has returned after a previous
remission.

If you are found to be eligible to take part in this study, you will receive cladribine by
vein over 2 hours once a day for 5 days in a row. You will only receive 1 cycle (5 days) of
this treatment. Then you will receive rituximab by vein once a week for 8 weeks. Treatment
with rituximab will start around Day 28.

After the first dose of each study drug has been given to you at MD Anderson, all later doses
of both drugs can be given to you by your community doctor in your home town. You will have a
weekly blood tests (about 1 teaspoon each) for the first 4 weeks and before receiving
rituximab. You will have a repeat bone marrow biopsy before starting rituximab in order to
see how much disease is left behind. You will then have a blood test (about 1 teaspoon) every
2 to 4 weeks while you are receiving rituximab. A bone marrow biopsy will also be done at the
end of rituximab treatment.

You will be taken off the study if the disease gets worse or if intolerable side effects
occur. After completing rituximab, you will return for a follow-up visit every 3 months for
one year. At these visits you will have blood (about 1 teaspoon) tests performed.

Inclusion Criteria:

1. Age 18 years and older

2. Diagnosis of HCL established by bone marrow examination

3. Patients with relapsed disease are eligible if they have had no more than one prior
therapy

4. Women of child-bearing potential must use birth control (oral contraceptive, barrier,
abstinence or any other acceptable method) for the duration of the study

5. Performance status
6. Adequate renal function: creatinine less than or equal to 2.0 unless related to the
disease

7. Adequate liver function: bilirubin less than or equal to 3.0, transaminases less than
or equal 3 x upper limit of normal unless related to the disease

8. No prior investigational agent in the 4 weeks prior to initiation of therapy

Exclusion Criteria:

1. Unable or unwilling to sign the consent form

2. Known infection with HIV, hepatitis B or C

3. Presence of active infection

4. Presence of CNS metastases

5. New York Heart Association Classification III or IV heart disease (See Appendix I)

6. Prior chemotherapy (last 4 weeks)