The primary objective of the study is to assess the pharmacokinetic (PK) similarity of SCT400 versus rituximab (MabThera®) in patients with CD20+ B-cell Non-Hodgkin's Lymphoma.

The secondary objective of the study is to evaluate the pharmacodynamics (PD) and safety of SCT400 versus rituximab (MabThera®), as well as the presence of human anti-chimeric antibodies (HACA).

Inclusion Criteria:

1. aged from 18 to 75 years;
2. having histologically confirmed NHL expressing CD20 antigen;
3. having obtained CR (complete remission) or CRu (uncertain complete remisson) after the prior therapy;
4. ECOG performance status of 0 to 1
5. expected survival of at least ≥ 3 months;
6. signed an informed consent form which was approved by the institutional review board of the respective medical center .

Exclusion Criteria:

1. had received rituximab or other anti-CD20(+) monoclonal antibody treatment within 1 year before enrollment;
2. having to be at least 4 weeks beyond prior anticancer therapy including corticosteroid, or have not recovered from significant toxicities of prior therapy;
3. participating in other clinical trial within 30 days before enrolment;
4. 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);
5. had received live vaccine within 4 weeks prior to study entry;
6. with other malignancies ; or central nervous system (CNS) lymphoma, AIDS-related lymphoma; or active opportunistic infection, a serious nonmalignant disease;
7. 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,
8. recent major surgery (within 28 days prior to study entry );
9. with a history of allergic reaction or protein product allergy including murine proteins;
10. pregnant or lactating or not accepted birth control methods including male patients.