Reduced Pathogen‐Specific T Cell Response With BCMA‐Targeted T Cell‐Engaging Therapy to Multiple Myeloma

ABSTRACT Introduction Bispecific antibody (BsAb) treatment can lead to increased infections in myeloma patients. Methods We used ELISpot and flow cytometry to test the T cell response to BCMA‐CD3‐bispecific T cell engager (BiTE) pavurutamab (PAV) and BCMA‐expressing myeloma cells after in vitro culture. Results Reduced pathogen‐specific responses were found in T cells cultured with PAV yet they killed myeloma cells. In an exploratory study, reduced pathogen‐specific memory T cell responses were detected in PBMCs from four myeloma patients responding to BCMA‐targeted BsAb therapy. Conclusion Our preliminary observation and its link to infection should be followed up in a larger study. Trial Registration The authors have confirmed clinical trial registration is not needed for this submission.