Bendamustine Hydrochloride is a bifunctional basal alkylating agent with antitumor and cytocidal effects. Its antitumor and cytocidal effects are mainly attributed to the cross-linking of DNA single strands and duplexes by alkylation, which disrupts the function of DNA and DNA synthesis, and also causes cross-linking between DNA and proteins, and between proteins and proteins, which exerts antitumor effects. The response rate of bendamustine alone or in combination with chemotherapy for the treatment of Hodgkin’s lymphoma and non-Hodgkin’s lymphoma is 61% – 97% and 41% – 48%, respectively. It is mainly used in the treatment of the following malignancies: non-Hodgkin’s lymphoma, plasma cell tumor (multiple myeloma), and chronic lymphocytic leukemia (CLL). The usual dose in lymphoma or myeloma is 50–60 mg/m2/d for 3–5 days or 100–120 mg/m2 every 3 —4 weeks. Bendamustine is an effective alkylating agent in a variety of lymphomas, including follicular lymphoma, set cell lymphoma, diffuse large B-cell lymphoma, and chronic lymphocytic lymphoma. Treatment of a case of relapsed refractory Hodgkin’s lymphoma with monotherapy (90 mg/m2) has been reported, and complete remission was achieved after 2 courses of therapy with insignificant side effects. In relapsed refractory set of lymphomas (MCL), a retrospective clinical study from Spain, bendamustine was used alone or in combination with other drugs for relapsed refractory MCL. 58 patients, median age 71 years, were treated with bendamustine in combination with melphalan, with a median duration of 5 courses (1-8) and an overall treatment response (ORR) of 84%, of which 53% were achieved in complete remission or indeterminate complete remission (CR/uCR). Median progression-free survival (PFS) was 16 months, and PFS for patients who achieved CR/uCR was 33 months. The median survival (OS) was 30 months. Death occurred only in one elderly patient of 79 years with very poor general condition. A total of 280 sessions with only 12 (4%) hospitalizations due to neutrophil deficient fever achieved a good outcome even in patients who had previously undergone multiple lines of therapy. Also, in transplant pretreatment: myelosuppression, GVHD and relapse are the main causes of death in recurrent lymphoma treated with stem cell transplantation. In this trial, bendamustine climbing doses (70, 90, 110, 130 mg/m2 for 3 days) combined with fludarabine and melphalan were tested as a pretreatment regimen for non-cleared allogeneic hematopoietic stem cell transplantation for relapsed lymphoma (n=41) and chronic lymphocytic leukemia (n=15). 10 patients entered the dose escalation trial in the phase I clinic and no dose limiting adverse reactions. 46 cases entered phase II clinic with a maximum dose of 130 mg/m2 for 3 days. The incidence of grade II–IV aGVHD was 11%. 2 year incidence of severe cGVHD was 26%. The median follow-up was 26 months (6-50 months), and the 2-year OS and PFS were 90% and 75%, respectively. Therefore, it is considered that in relapsed CLL and lymphoma, the use of a new bendamustine-based non-cleared marrow pretreatment regimen is safe and effective.