A First‐In‐Human Phase 1 Study of a Novel BCMA × CD3 Bispecific T Cell Engager EMB ‐06 in Relapsed or Refractory Multiple Myeloma

To the Editor, Relapsed or refractory multiple myeloma (MM) remains a challenging disease to treat despite the introduction of immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs), and anti-CD38 monoclonal antibodies (mAbs) which have substantially improved patient survival [1]. BCMA (B cell maturation antigen)—with high expression in plasmablasts (PBs) and mature plasma cells (PCs)—has emerged as a key therapeutic target in MM. In heavily pretreated patients with RRMM, BCMA-targeted CAR-T and bispecific TCEs therapies [2, 3] have demonstrated objective response rates (ORR) ranging from 61% to 97%. However, these treatments are associated with a high overall incidence of cytokine release syndrome (CRS) at 66.7%–94.8%, and immune effector cell-associated neurotoxicity syndrome (ICANS) at rates of 3%–18%.