Safety and Efficacy of Anti-GPRC5D CAR-T Cells Therapy in the Treatment of r/r MM

Inclusion Criteria: 1. The patient or his/her guardian understands and voluntarily signs the informed consent, and is expected to complete the follow-up examination and treatment of the study procedure; 2. Age 18-75 years old, gender unlimited; 3. Patients diagnosed with multiple myeloma according to International Myeloma Working Group(IMWG) diagnostic criteria; 4. Subjects who had failed treatment with at least 3 drugs of different mechanisms (including chemotherapy, proteasome inhibitors, immunomodulators, etc.), or had progressed or relapsed during the last treatment period or within 6 months after the end of treatment; 5. The presence of measurable lesions at screening was determined according to any of the following criteria, defined as: (1) serum monoclonal immunoglobulin (M-protein) level ≥1.0 g/dL; (2) urine M protein level ≥200 mg/ 24h; (3) Light chain multiple myeloma diagnosed with no measurable lesion in serum or urine: serum immunoglobulin free light chain ≥10 mg/dL and serum immunoglobulin κ/γ free light chain ratio abnormal; 6. The patient has recovered from the toxicity of the prior treatment, i.e., CTCAE toxicity grade \< 2 (unless the abnormality is related to the tumor or is stable as judged by the investigator and has little impact on safety or efficacy); 7. Eastern cooperative oncology group (ECOG) score is 0-2; 8. Survival is expected to be greater than 3 months; 9. Adequate liver , kidney and cardiopulmonary function; 10. Willingness to complete the informed consent process and to comply with study procedures and visit schedule. Exclusion Criteria: 1. Have been diagnosed with or treated for aggressive malignancies other than multiple myeloma; 2. Prior antitumor therapy (prior to blood collection for CAR-T preparation) : targeted therapy, epigenetic therapy, or investigational drug therapy within 14 days or at least 5 half-lives, whichever is shorter; 3. It is suspected that MM has involved the central nervous system or meninges and has been confirmed by MRI or CT, or there are other active central nervous system diseases; 4. Clinically significant central nervous system diseases, such as epilepsy, cerebrovascular ischemia/hemorrhage, dementia, cerebellar disease, psychosis, active central nervous system involvement or cancerous meningitis; 5. HBsAg or HBcAb are positive, and the quantitative detection of hepatitis B virus(HBV) DNA in peripheral blood is more than 100 copies / L;hepatitis C virus (HCV) antibody and HCV RNA in peripheral blood are positive; HIV antibody positive; Syphilis antibody is positive in the first screening; 6. Pregnant or breastfeeding; 7. Severe active viral, bacterial or uncontrolled systemic fungal infections; Hereditary bleeding / coagulation diseases, history of non traumatic bleeding or thromboembolism, other diseases that may increase the risk of bleeding, etc;Patients who received autologous hematopoietic stem cell transplantation (ASCT) within 8 weeks before screening, or who plan to undergo ASCT during the study period; 8. Any unstable systemic disease: including but not limited to unstable angina, cerebrovascular accident or transient cerebral ischemia (within 6 months before screening), myocardial infarction (within 6 months before screening), congestive heart failure \[New York Heart Association (NYHA) classification ≥ grade III\], severe arrhythmia with poor drug control, liver, kidney or metabolic diseases; 9. Had hypersensitivity or intolerance to any drug used in this study; 10. Persons with serious mental illness; 11. Alcoholics or persons with a history of drug abuse; 12. Systemic diseases judged by researchers to be unstable: including but not limited to severe liver, kidney or metabolic diseases requiring drug treatment; 13. Patients with acute/chronic graft-versus-host disease (GVHD) or requiring immunosuppressive therapy for GVHD within 6 months prior to screening; 14. Any unsuitable to participate in this trial judged by the investigator.