A Study of OL-101 Injection in Patients with Relapsed or Refractory Multiple Myeloma (RRMM)

Inclusion Criteria: * Documented diagnosis of multiple myeloma according to the 2014 IMWG diagnostic criteria * Relapsed/refractory multiple myeloma as defined by: 1\) Received at least 3 prior lines of MM treatment (must include a PI, an IMiD, and an anti-CD38 antibody). 2）Disease progression within 12 months of the most recent anti-MM therapy; or disease progression within the past 6 months and subsequently lack response to the most recent line of therapy. * Measurable disease at screening as defined by any of the following: 1. Serum monoclonal paraprotein (M-protein) level ≥1.0 g/dL or urine M-protein level ≥200 mg/24 hours; or 2. Light chain multiple myeloma without measurable disease in the serum or the urine: Serum immunoglobulin free light chain ≥10 mg/dL and abnormal serum immunoglobulin kappa lambda free light chain ratio. * Positive expression of either BCMA or GPRC5D on bone marrow plasma cells; must be GPRC5D expression positive if previously received BCMA targeted therapy * ECOG 0-1 * Expected life expectancy exceeds 12 weeks * Adequate bone marrow reserve or organ function meeting the following criteria: 1. Hemoglobin ≥ 70 g/L 2. Platelet count ≥ 50 × 10\^9/L 3. Absolute lymphocyte count ≥ 0.3×10\^9/L 4. Absolute neutrophil count ≥ 1.0 × 10\^9/L 5. Alanine aminotransferase (ALT) and Aspartate aminotransferase (AST) ≤ 2.5 times the upper limit of normal (ULN) 6. Total bilirubin ≤ 2 times ULN; except in subjects with congenital bilirubinemia (such as Gilbert syndrome, in which case the direct bilirubin ≤1.5 × ULN is required) 7. Creatinine clearance ≥ 60 mL/min (calculated by Cockcroft-Gault equation). 8. corrected serum calcium ≤12.5 mg/dL (≤3.1 mmol/L) or free ionized calcium ≤6.5 mg/dl (≤1.6 mmol/L) 9. SpO2\>92% on room air 10. Left ventricular ejection fraction (LVEF) ≥ 50% as assessed by echocardiogram; no clinically meaningful pericardial effusion by ultrasound Exclusion Criteria: * Solitary plasmacytoma * Known active central nervous system (CNS) involvement or exhibits clinical signs of CNS involvement of multiple myeloma. * Received allogeneic stem cell transplant; received autologous stem cell transplant within 12 weeks before screening * Active second primary malignant tumor, exclude the following: cured non- melanoma skin cancer, non-metastatic prostate cancer, cervical carcinoma in situ, ductal or lobular carcinoma in situ of the breast * Any other significant medical disease, abnormality, or condition that, in the investigator judgment, may make the patient unsuitable for participation in the study or put the patient at risk. * Plasma cell leukemia, Waldenström's macroglobulinemia, POEMS syndrome, or primary AL amyloidosis.