A Study Comparing GB241 And Rituximab in Patients With B-cell Non-Hodgkin's Lymphoma

Inclusion Criteria: * having histologically confirmed NHL expressing CD20 antigen * having obtained CR (complete remission) or CRu (uncertain complete remission) after the prior therapy * signed an informed consent form which was approved by the institutional review board of the respective medical center * aged from 18 to 75 years * ECOG performance status of 0 to 1 * expected survival of at least ≥ 3 months Exclusion Criteria: * had received rituximab or other anti-CD20(+) monoclonal antibody treatment within 1 year before enrollment * having to be at least 4 weeks beyond prior anticancer therapy including corticosteroid, or have not recovered from significant toxicities of prior therapy * participating in other clinical trial within 30 days before enrolment * with serious hematologic dysfunction (white blood cell count of \<3.0×103/uL; absolute neutrophil count of \<1.5×103/ uL; platelet count of \< 75×103/uL; hemoglobin level of \< 8.0 g/dL); hepatic dysfunction (total bilirubin level of \> 1.5×ULN; aspartate amino transferase (AST) and alanine amino transferase (ALT) levels of \>2.5 × ULN; renal dysfunction (serum creatinine level of \> 1.5×ULN ); and International normalized ratio (INR) and partial thromboplastin time or activated partial thromboplastin time (aPTT) \> 1.5 × ULN (unless on therapeutic coagulation) * had received live vaccine within 4 weeks prior to study entry * with other malignancies ; or central nervous system (CNS) lymphoma, AIDS-related lymphoma; or active opportunistic infection, a serious nonmalignant disease * seropositive for HCV antibody, or HIV antibody, or hepatitis B virus surface antigen (HBsAg). HBc antibody seropositive, but HBV DNA and HBsAg negative patients may participle following consultation with a hepatitis expert regarding monitoring and use of HBV antiviral therapy, and provided they agree to receive treatment as indicated * recent major surgery (within 28 days prior to study entry ) * with a history of allergic reaction or protein product allergy including murine proteins * pregnant or lactating or not accepted birth control methods including male patients * patients considered unsuitable by PI * previous malignant tumor except cured cervical cancer,basal cell carcinoma and squamous cell skin cancer * active opportunistic infections and other serious non neoplastic diseases