The following criteria is provided for health care professionals.

Inclusion Criteria:

1. Voluntarily signed consent;
2. Age of ≥ 18;
3. Received sufficient prior lines of myeloma therapy;
4. Received treatment with at least one proteasome inhibitor, one IMiD and daratumumab.
5. The patients should have measurable disease per IMWG definition.
6. Estimated life expectancy > 12 weeks;
7. ECOG performance score 0-1;
8. Patients should have reasonable CBC counts, renal and hepatic functions;
9. Sufficient venous access for leukapheresis collection, and no other contraindications to leukapheresis;
10. Women of childbearing age must undergo a serum pregnancy test with negative results before screening, and are willing to use effective and reliable method of contraception for at least 6 months after T cell infusion;
11. Men must be willing to use effective and reliable method of contraception for at least 6 months after T cell infusion.

Exclusion Criteria:

1. Pregnant or lactating women;
2. HIV, active hepatitis C virus (HCV), or active hepatitis B virus (HBV) infection;
3. Any uncontrolled active infection;
4. AEs from previous treatment that have not recovered;
5. Patients who have had anti-BCMA therapy;
6. Patients who have graft versus host disease (GvHD);
7. Patients have received stem cell transplantation less than 12 weeks before leukapheresis;
8. Patients have received any anti-cancer treatment before leukapheresis;
9. Patients have received steroids before leukapheresis or lymphodepletion;
10. Patients have plasma cell leukemia, Waldenström macroglobulinemia, POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome or clinically significant symptomatic immunoglobulin light chain (AL) amyloidosis with evidence of end-organ damage;
11. Patients have been administered live attenuated vaccine before leukapheresis or lymphodepletion;
12. Patients allergic to Flu, Cy, tocilizumab, dimethyl sulfoxide (DMSO) or CT053 CAR BCMA T cell;
13. Patients have clinical significant cardiac conditions that researchers believe that participating in this clinical trial may endanger the health of the patients;
14. Patients have clinical significant pulmonary conditions;
15. Patients are known to have active autoimmune diseases including but not limited to psoriasis, rheumatoid arthritis and other needs of long-term immunosuppressive therapy;
16. Patients with second malignancies in addition to MM are not eligible;
17. Patients have central nervous system (CNS) metastases or CNS involvement;
18. Patients have significant neurologic disorders;
19. Patients are unable or unwilling to comply with the requirements of clinical trial;
20. Patients have received major surgery prior to leukapheresis or prior to lymphodepletion.