Clinical Study of CAR-BCMA T Cells in Patients With Refractory or Relapsed Multiple Myeloma

Inclusion Criteria: 1. Patients aged between 18 \~ 70 with relapsed or refractory multiple myeloma. 2. Bone marrow sample is confirmed as BCMA-positive by flow cytometry or pathological examination. 3. Patients with relapsed or refractory multiple myeloma who meet the following conditions: * 1\) Curative efficacy is little or disease progressed after 2 courses of standard treatment regimen; * 2\) Disease relapsed after chemotherapy or HSCT. Curative efficacy is little or disease progressed after 2 courses of original treatment regimen; * 3\) More than 60 days between last treatment and disease progression; * 4\) Autologous or allogeneic SCT is not available at present, or patient refuses to receive SCT; * 5\) Disease progression is defined as per "Chinese Guidelines for Diagnosis and Treatment of Multiple Myeloma (Revision in 2015)". At least one of the following conditions should be met: * \- i. Serum M-protein increases ≥ 25% (absolute increase should be ≥ 5 g/L). If serum M protein is ≥ 50 g/L at baseline, increase of serum M protein can be ≥ 10 g/L; * \- ii. Urine M-protein increases ≥ 25% (absolute increase should be ≥ 200 mg/24 h); * \- iii. If the serum and urine M-protein are not detectable, a ≥ 25% increase in the difference between involved and uninvolved FLC levels is required (absolute increase should be ≥ 100 mg/L); * \- iv. Bone marrow plasma cell percentage increases ≥ 25% (absolute increase should be ≥ 10%); * \- v. Size of existing bone lesions or soft tissue plasmacytomas increases by ≥ 25%, or development of new lytic bone lesions or soft tissue plasmacytomas; * \- vi. Development of hypercalcemia that can be attributed to plasma cell proliferative disorder (corrected calcium is \> 2.8 mmol/L or 11.5 mg/dL); * \- vii. Disease progression must be confirmed by 2 sequential assessments. 4. Expected survival \> 12 weeks. 5. Disease is measurable, and at least one of the following conditions should be satisfied: * 1\) Serum M-protein is ≥ 10 g/L; * 2\) 24-hour urine M-protein is ≥ 200 mg; * 3\) Serum FLC is ≥ 5 mg/dL; * 4\) Plasmacytomas that can be measured or evaluated by imaging; * 5\) Bone marrow plasma cell percentage is ≥ 20%. 6. ECOG scores 0 - 1. 7. Adequate venous access for apheresis and venous blood sampling, and no other contraindications for leukapheresis. 8. WBC ≥ 1.5×10\^9/L, PLT ≥ 45×10\^9/L; 9. Serum creatinine ≤ 1.5 ULN. 10. ALT ≤ 2.5 ULN, AST ≤ 2.5 ULN. The above lab results should not include those obtained from continuous supportive treatment that is ongoing. Exclusion Criteria: Patients with any of the following conditions are not eligible for this study. 1. Transduction of target lymphocytes \< 10%, expansion in response to αCD3/CD28 costimulation \< 5-fold. 2. Pregnant or lactating women. 3. HIV positive, or HCV positive 4. Uncontrolled active infection, including active tuberculosis and HBV DNA copies ≥ 1×10\^3 copies/mL. 5. Concurrent use of systemic steroids. Recent or current use of inhaled steroids is not exclusionary. 6. Allergic to immunotherapies and related drugs. 7. Patients with heart disease for which treatment is needed or with poorly controlled hypertension. 8. Hyponatremia: serum sodium level \< 125 mmol/L. 9. Baseline serum potassium \< 3.5 mmol/L (taking potassium supplements before participating in the study to raise potassium level is acceptable). 10. Previous treatment with chemoradiotherapy, immunotherapy and tumor-targeting drug conducted 2 weeks prior to participation in this study or blood collection. 11. Patients have undertaken immunosuppressor for graft-versus-host disease (GVHD) within 4 weeks before participation in this study or blood collection, or the patient is diagnosed with acute or chronic GVHD. 12. Other severe disease that may restrain patients from participating in this study (e.g. diabetes, severe cardiac dysfunction, myocardial infarction or unstable arrhythmias or unstable angina in recent 6 months, gastric ulcer, active autoimmune disease, etc.).