Safety and Efficacy Study of Bendamustine to Treat Non-Hodgkin Lymphoma

Inclusion Criteria: * 18 to 75 years * B-cell indolent lymphoma proved by biopsy, exclude CLL/SLL * Rituximab refractory or relapsed lymphoma patients * At least 1 measurable tumor with shortest diameter being of \> 1.0cm and longest diameter being of \> 1.5cm * ECOG PS ≤ 2 * Anticipated Survival is more than 3 months * Hematopoietic function is normal during 14 days before enrollment (unless those abnormities related to lymphoma aggression), including: hemoglobin (Hb) ≥ 8.0g/dl (5.0mmol/L); absolute neutrophil count (ANC) ≥ 1.5X109/L; Platelet count (PLT) ≥ 80X109/L. Acceptable range for abnormities related to lymphoma aggression: Platelet count (PLT) ≥ 50X109/L; White blood cell count (WBC) ≥ 3.5X109/L; Absolute neutrophil count (ANC) ≥ 1.0X109/L * Female subjects should not be pregnant and breast-feed, should have contraceptive method during the clinical trial and 12 months thereafter. * Subject (or his/her legal representative) agrees to participate the trial and sign the informed consent form Exclusion Criteria: * Those who can not tolerate bendamustine treatment according to investigators view * Transferred to high grade malignant lymphoma (from low grade follicular lymphoma) * 3b grade follicular lymphoma * With central nervous system diseases or medical history (e.g., central nervous system lymphoma or lymphoma related meningitis ) * With other anticancer treatment during the last 4 weeks * Regularly administrated corticosteroid during the last 4 weeks, unless the dose is less or equivalent to 20mg/d prednisone * Had tumors or have other tumors, not including non-melanoma skin cancers and cervical carcinoma in situ be treated properly * Underwent surgical operation within 28 days before enrollment (exclude lymph node biopsy) * Renal disfunction: serum creatinine is more than 1.5 times of upper limit of normal value * Hepatic insufficiency: serum total bilirubin is \> 1.5 times of upper limit of normal value; AST, ALT is \> 2.5 times of upper limit of normal value * Known HIV infection or HBV, HCV related active infections; HBsAg is positive; HBcAb is positive and virus copy number is \> 1000 * For patients with other severe medical diseases interfering with their participations of this study(e.g., infections and diabetes not controlled well, gastric ulcer, other lung diseases, active autoimmune diseases), the suitability of participation is judged by investigators * Patients participated in other clinical studies and got medical treatments within 30 days prior to enrollment of this trial * Other medical and psychological conditions that influence the patients participation or signing of informed consent form