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).