Immunoglobulin A Subtype and Survival After Upfront Autologous Stem Cell Transplantation in Multiple Myeloma: A Real-World Cohort from the Bortezomib Era

Abstract

Simple Summary Multiple myeloma is a cancer of plasma cells, which secrete an abnormal antibody. The class of that antibody is identified in every patient during routine diagnostic work-up at no additional cost, but it plays no part in the scores used to assess disease aggressiveness. We reviewed 196 patients who received an autologous stem cell transplant at a single center between 2009 and 2023, all of whom were treated with bortezomib-based induction before anti-CD38 antibodies became routine first-line use. Patients whose myeloma produced immunoglobulin A progressed and died sooner than those producing immunoglobulin G. After accounting for stage, age, depth of response before transplantation, induction treatment, and year of transplantation, the difference in progression remained, while the difference in survival was smaller and less certain. Chromosomal testing was too incomplete in this cohort to determine whether the difference reflects known genetic risk factors, and progression was recorded differently between patient groups, so overall survival is the more dependable of our two endpoints. We do not propose that the antibody class should change treatment. We suggest that it be recorded and tested in larger studies with complete genetic characterization, where its value, if any, can be established.