Inclusion Criteria:

- Patients with CD 20 positive, relapsed/refractory indolent lymphoma. (Regimens of
prior chemotherapy are limited to 2; prior rituximab treatments up to 16 times are
allowed.)

- Patients with measurable lesions (> 1.5 cm).

- Patients who have not received any treatment for more than 4 weeks after completing
previous therapies (6 months in the case of antibody therapies).

- ECOG performance status: 0 - 1

- Patients with adequately maintained organ functions.

Exclusion Criteria:

- Patients with infectious disease, serious complications, serious gastrointestinal
symptoms, serious bleeding tendency, serious CNS symptoms, fever interstitial pneumonia or pulmonary fibrosis, active other malignancies, autoimmune
hemolytic anemia or the history of the disease, or glaucoma.

- Patients who are positive for HBs antigen, HCV antibody, or HIV antibody.

- Patients who received G-CSF or transfusion within 1 week before the registration.

- Patients with the history of allergies to purine nucleoside analogue.

- Patients who experienced serious hypersensitivity or anaphylaxis to rituximab or
mouse protein-derived products.

- Patients who had ever received prior therapy with fludarabine phosphate injection,
pentostatin, cladribine, SH T 586, blood stem cell transplant, or monoclonal antibody
therapy other than rituximab to NHL (including radioimmunotherapy).

- Patients who had progressive disease within 6 months of receiving therapy including
rituximab.

- Women who are pregnant, of childbearing potential, or lactating.

- Patients who do not agree to practice contraception.