QLS4131 Combination Therapy in Malignant Plasma Cell Neoplasms

Inclusion Criteria: \- Diagnosis of multiple myeloma confirmed according to the 2016 International Myeloma Working Group (IMWG) diagnostic criteria, or diagnosis of plasma cell leukemia and primary light-chain amyloidosis confirmed in accordance with relevant guidelines.; For patients with multiple myeloma and plasma cell leukemia, measurable disease at screening is defined as meeting any one of the following: * Serum M-protein ≥0.5 g/dL (5 g/L); * Urine M-protein ≥200 mg/24 hours; * Serum immunoglobulin free light chain ≥10 mg/dL (100 mg/L) with an abnormal serum immunoglobulin κ/λ free light chain ratio. For patients with light-chain amyloidosis:Measurable disease is defined as Involved serum free light chain ≥ 50 mg/L with an abnormal light chain ratio,ordifference between involved and uninvolved serum free light chains (dFLC) ≥ 50 mg/L. Exclusion Criteria: * History of Grade 3 or higher cytokine release syndrome (CRS) associated with any T-cell redirecting therapy (e.g., CD3-redirecting technologies or CAR-T cell therapy); * Patients who received any of the following prior anti-tumor therapies before the first dose of investigational productt: 1. Previous treatment with BCMA/GPRC5D/CD3-targeted therapy; 2. Received any anti-tumor therapy within 4 weeks prior to the first dose, except for the following circumstances: * Cytotoxic therapy or small-molecule targeted therapy within 2 weeks or 5 half-lives, If the half-life is unknown, the washout period shall be 2 weeks (whichever is longer); * Immunomodulatory drug therapy within 7 days * Genetically modified adoptive cell therapy within 3 months.; * Traditional Chinese medicine with anti-tumor indications within 14 days.; * Radiotherapy within 14 days * Prior intolerance to Pomalidomide (applies to treatment cohorts containing Pomalidomide); * Prior intolerance to Lenalidomide (applies to treatment cohorts containing Lenalidomide); * Prior intolerance to QL2109 (applies to treatment cohorts containing QL2109).