The purpose of the study is to compare the efficacy of QLS32105 (SC) in combination with Pomalidomide, and QLS32105 (SC) in combination with QL2109 or Daratumumab, and QLS32105 (SC) in combination with QL2109 or Daratumumab and Pomalidomide, and QLS32105(SC) in combination with Bortezomib and Lenalidomide.

Inclusion Criteria:

• Diagnosis of multiple myeloma confirmed according to the 2016 International Myeloma Working Group (IMWG) diagnostic criteria;

• Prior therapy: Relapsed, progressed, or intolerant to ≥1 prior line of anti-multiple myeloma therapy;

• Measurable disease at screening, defined by at least one of the following:

  • Serum M-protein ≥1.0 g/dL (10 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.

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);

• Prior anti-myeloma therapies within the specified timeframes before enrollment:

  • Previous treatment with GPRC5D-targeted therapy;
  • Genetically modified adoptive cell therapy (e.g., chimeric antigen receptor T-cell [CAR-T], natural killer [NK] cell therapy) within 3 months;
  • Targeted therapy, investigational drugs, or invasive investigational medical devices within 21 days or 5 half-lives (whichever is longer);
  • Bispecific antibody therapy for multiple myeloma within 21 days or 5 half-lives (whichever is longer);
  • Cytotoxic therapy or monoclonal antibodies within 21 days;
  • Proteasome inhibitor therapy within 14 days;
  • Immunomodulatory drug therapy within 7 days;

• Radiotherapy within 14 days (except low-dose palliative radiation [10-30 Gy]);

• Prior intolerance to Pomalidomide (applies to treatment cohorts containing Pomalidomide);

• Prior intolerance to Bortezomib (applies to treatment cohorts containing bortezomid);

• Prior intolerance to Lenalidomide (applies to treatment cohorts containing Lenalidomide);

• Prior intolerance to Daratumumab (applies to treatment cohorts containing Daratumumab).