XmAb24306 + cevostamab

XmAb24306 + cevostamab is an investigational combination therapy for relapsed/refractory multiple myeloma. **XmAb24306** is a recombinant interleukin-15 (IL-15)/IL-15 receptor alpha (IL-15Rα) Fc-fusion protein that acts as a cytokine immunotherapy by stimulating T cell and natural killer (NK) cell proliferation and activation. **Cevostamab** is a bispecific monoclonal antibody (T-cell engager) that targets both Fc receptor-homolog 5 (FcRH5) on multiple myeloma cells and the CD3 antigen on T-cells, thereby redirecting T-cell cytotoxicity toward malignant plasma cells. The combination is designed to enhance anti-tumor immune activity by simultaneously expanding the effector T-cell population (with IL-15R agonism) and directly engaging tumor-directed cytotoxicity (via FcRH5/CD3 engagement). Both agents are under development by Genentech, and ongoing early-phase trials are assessing safety, pharmacokinetics, and preliminary efficacy in patients with heavily pretreated multiple myeloma[1][3][5][7].