Inclusion Criteria:

- Patients with documented CD20-positive for lymphoma cells

- Patients with measurable lesions

- Relapsed or refractory after 1 to 3 prior therapeutic treatments for diffuse large
B-cell lymphoma.

- Patients who are expected to survive for at least 3 months

- Patients aged from 20 to 75 years at the time informed consent is obtained

- Performance Status (P.S.) of 0 to 1 at initial administration of the study drug

- Patients with adequately maintained organ functions

- Patients capable of personally giving voluntary informed consent in writing to
participate in the study

Exclusion Criteria:

- Patients who have been without treatment for less than 3 weeks after prior treatment

- Patients who can be candidates for autologous peripheral blood stem cell
transplantation at the discretion of the investigator.

- Patients who received adequate prior treatments and did not respond to any of them.

- Patients with central nervous system (CNS) involvement or patients with clinical
symptoms suggestive of CNS involvement.

- Patients with serious, active infections

- Patients with serious complications

- Patients with complications or medical history of serious cardiac disease

- Patients with serious gastrointestinal symptoms

- Patients with malignant pleural effusion, cardiac effusion, or ascites retention

- Patients positive for hepatitis B surface (HBs) antigen, hepatitis C virus (HCV)
antibody, or HIV antibody

- Patients with serious bleeding tendencies

- Patients with a fever of 38.0C or higher

- Patients with, or confirmed in the past to have had, interstitial pneumonia,
pulmonary fibrosis, or pulmonary emphysema

- Patients with active multiple primary cancer or patients with a history of other
malignant cancer within the past 5 years, except for basal cell cancer of the skin,
squamous cell cancer, or cervical cancer in situ

- Patients with, or confirmed in the past to have had, autoimmune hemolytic anemia

- Patients who received SyB L-0501 in the past

- Patients who received cytokine preparation such as erythropoietin or granulocyte
colony-stimulating factor (G-CSF) or blood transfusions within 2 weeks before the
examination at registration for this study

- Patients who received other investigational products or unapproved medication within
3 months before registration in this study