Efficacy and Safety Study of SH T 586 in Combination With Rituximab to Treat Low-Grade NHL

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 </=38 °C, 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.