• 1\. Age :18-75 years, male or female; 2. Meet the definition of relapsed/refractory multiple myeloma; 3. At least one of the following can be evaluated:

‣ Blood M protein level ≥10g/L;

⁃ 24-hour urine M protein level ≥200mg;

⁃ The difference between involved and uninvolved serum free light chain (dFLC) ≥100mg/L;

⁃ Extramedullary lesions with a diameterday≥2cm; 4. ECOG score 0-2 points; 5. Laboratory tests meet the following criteria:

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‣ Absolute neutrophil count (ANC) ≥1.0x109/L;

⁃ Platelets (PLT) ≥50x109/L;

⁃ Total bilirubin (TBIL) ≤1.5 times the upper limit of normal (ULN);

⁃ Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5 times ULN;

⁃ Creatinine clearance rate (Ccr) ≥30ml/min.