MRD-Adaptive Guided Immunotherapy With CAR-T for Transplant-Ineligible Patients With Multiple Myeloma

Inclusion Criteria: 1. Age ≥ 18 years and ≤ 75 years. 2. Participants with documented newly-diagnosed multiple myeloma according to IMWG diagnostic criteria. 3. Measurable disease at screening, defined as: Serum M-protein level ≥1.0 g/dL or urine M-protein level ≥200 mg/24 hours; or Light chain MM without measurable disease in serum or urine: serum Ig free-light chain (FLC) ≥10 mg/dL and abnormal serum Ig kappa lambda FLC ratio. 4. Patients deemed ineligible for high-dose chemotherapy with ASCT due to any of the following: Age ≥65 years; Investigator assessment of ineligibility; ECOG performance status 3-4; Repeated failure of hematopoietic stem cell mobilization; Patient's decision to defer ASCT. 5. Tumor cells were BCMA and GPRC5D positive. 6. Serum total bilirubin \<2 x upper limit of normal (ULN), serum AST and ALT \<3 x ULN, creatinine clearance ≥ 30mL/min (Cockroft-Gault formula). 7. Informed Consent/Assent: All subjects have the ability to understand and the willingness to sign a written informed consent. Exclusion Criteria: 1. Active amyloidosis. 2. Central nervous system involvement. 3. Prior BCMA-targeted therapy or CAR-T therapy. 4. Active hepatitis B or hepatitis C virus infection. 5. Known HIV infection. 6. Life expectancy \<6 months. 7. Woman who are pregnant or breastfeeding. 8. Evidence of uncontrolled dysfunction of heart, lung, brain, and other important organs. 9. Any other conditions that are not eligible for the trial in the judgement of the principal investigator.