The Efficacy and Safety of Pomalidomide and Bendamustine With Dexamethasone in Relapsed or Refractory Multiple Myeloma

Inclusion Criteria: * Age of 18-75, no gender limitations. * Ability of contraception during the experiment, no matter if they have suffered from infertility. * Relapsed or refractory to prior lenalidomide or/and bortezomib(either in combination or sequential)therapy (i.e. history of progression on therapy or within 60 days after completion) * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-2, life expectancy of more than 6 months. * Measurable disease: Serum M protein \> 10 g/L or Urine M protein ≥200 mg/24 hr or Elevated Free Light Chain per International Myeloma Working Group (IMWG) criteria, and abnormal ratio. * Absolute neutrophil count (ANC) \>1.0 x 109/L or \>1.0 x 109/L due to granulocyte/macrophage colony stimulating factor (GCSF and GMCSF), or if \>50% marrow involvement, there is no limitations * Platelet count \>50.0 x 109/L or if \>50% marrow involvement, there is no limitations. * Total bilirubin ≤ 2.0mg/dL, and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) \< 3 times the upper limit of normal. * Serum creatinine ≤2.0 mg/dL or creatinine clearance ≥60ml/min. * Agree to take anticoagulant drugs, included but not limited to aspirin. * Agree to sign the informed consent form. Exclusion Criteria: * Patients with known sensitivity to pomalidomide or bendamustine or dexamethasone and their accessories. * Patients with primary systemic amyloidosis or monoclonal gammopathy of undetermined significance or smoldering multiple myeloma. * Patients with active new thrombosis or disagree to take anticoagulant drugs, included but not limited to aspirin. * Active treatment or intervention for other malignancy or need active treatment within 4 weeks of starting study treatment. Patients with nonmelanoma skin cancer or carcinoma in situ of any type are not excluded if they have undergone complete resection. * Central nervous system involvement. * Systemic treatment with immunodepressants or steroids. * Ongoing or active systemic infection, active hepatitis B virus infect, active hepatitis C infection, or known human immunodeficiency virus (HIV) positive * Evidence of current uncontrolled cardiovascular conditions, including uncontrolled hypertension, uncontrolled cardiac arrhythmias, symptomatic congestive heart failure(NT-Pro-BNP≥1800pg/mL), unstable angina, or myocardial infarction within the past 6 months. * Infection requiring systemic antibiotic therapy or other serious infection. * Comorbid systemic illnesses or other severe concurrent disease which, in the judgment of the investigator, would make the patient inappropriate for entry into this study or interfere significantly with the proper assessment of safety and toxicity of the prescribed regimens. Psychiatric illness/social situation that would limit compliance with study requirements. * Under other clinical trial procedures. * Female patients who are lactating or pregnant. * Other patients not appropriate for the trial in the judgment of the investigator.