• 18 to 75 years of age (inclusive of critical values), either gender.

• The subject was previously diagnosed with multiple myeloma and had received 1-2 lines of therapy (including chemotherapy regimens based on proteasome inhibitors and immunomodulatory agents, with each line of therapy receiving at least 1 full cycle ; Documented disease progression during or within 12 months after the most recent anti-myeloma therapy.

• Subjects was lenalidomide-refractory during prior therapy.

• ECOG score of 0 or 1.

• Subjects must have appropriate organ function and meet all of the following laboratory test results before enrollment:

⁃ (1) Haematology: absolute neutrophil count (ANC) ≥1×10\^9/L (support with growth factor is allowed, but must not have received supportive treatment within 7 days before the laboratory test); Absolute lymphocyte count (ALC) ≥0.3×10\^9/L; Platelets ≥50×10\^9 / L (must not have received platelet transfusion within 7 days prior to laboratory test); Hemoglobin ≥60g/L (must not have received red blood cells transfusion within 7 days prior to laboratory test); (2) Hepatic function: alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5 times of upper limit of normal (ULN); Serum total bilirubin ≤1.5 times of ULN; (3) Renal function: creatinine clearance (CrCl) calculated by Cockcroft-Gault formula ≥ 40 ml/min; (4) Coagulation: fibrinogen≥1.0 g/L; activated partial thromboplastin time (APTT) ≤ 1.5×ULN, pro-thrombin time (PT) ≤ 1.5 × ULN; (5) Pulse oxygen saturation \> 91%; (6) Left ventricular ejection fraction (LVEF)≥50%;

⁃ 6\. Subjects agree to use effective tools or drug contraception (excluding safe period contraception) after signing the informed consent form.

⁃ 7\. Subjects must agree to sign or personally sign an ethics committee-approved informed consent form before starting any screening procedures.