Safety and Efficacy of IM21 Car-t Cells in Patients With Recurrent or Refractory BCMA Positive Multiple Myeloma

Inclusion Criteria:

1. The patient had multiple myeloma (according to the updated IMWG diagnosticcriteria)Active (symptomatic) myeloma

2. Refractory and recurrent multiple myeloma Refractory definition: 1) treated with atleast second-line bortezomib or lenalidomide 2) determined by the clinician Definitionof recurrence: refer to NCCN clinical guidelines for multiple myeloma (2016. V2),including recurrence after transplantation.

3. Age: 18 to 80 years old;

4. The expected survival time was more than 3 months;

5. ECoG score 0-2 (refer to Annex 2)

6. Hemoglobin (HB)≥80g/L; absolute neutrophil count (ANC)>1×10^9/L; plateletcount(PLT)≥50×10^9/L. Those who voluntarily participated in the experiment and signed informed consent.

Exclusion Criteria:

1. High risk organ involvement patients: tumor invasion of central nervous system,gastrointestinal tract,lung,pericardium,one of the major vessels;

2. Those who have graft-versus-host reaction and need to use immunosuppressants, or whohave autoimmune diseases;

3. Chemotherapy or radiotherapy was used within 3 days before blood collection;

4. Patients who used systemic steroids within 5 days before blood collection (exceptthose who have recently or are currently using inhaled steroids);

5. The patients who used drugs to stimulate the production of bone marrow hematopoieticcells within 5 days before the blood collection period;

6. Those who have previously used any gene therapy products;

7. History of epilepsy or other central nervous system diseases;

8. New York Heart Association (NYHA) grade III or above (refer to Annex 3) (for patientswith heart disease, this assessment is required);

9. Creatinine > 1.5 times normal upper limit, ALT / AST>3 times normal upper limit orbilirubin >2 times normal upper limit;

10. Active hepatitis B or hepatitis C virus, HIV or other uncured active infections;

11. Pregnant or lactating women;

12. Those who suffer from other uncontrolled diseases are not suitable to join the study;Any situation that the researchers believe may increase the risk of subjects orinterfere with the test results.