Impact of clonal plasma cells in autografts on outcomes in high-risk multiple myeloma patients

Most patients with multiple myeloma (MM) undergoing autologous hematopoietic stem cell transplantation (autoHCT) eventually relapse, perhaps due to the presence of clonal plasma cells (CPC) in the autograft. We conducted a retrospective analysis to evaluate the impact of CPC in the autograft on the outcomes of high-risk chromosomal abnormalities (HRMM) patients undergoing autoHCT between 2008 and 2018. Patients were divided into CPC+ or CPC− in the autograft by next-generation flow cytometry (NGF). There were 75 CPC + autografts (18%) and 341 CPC− (82%). The CPC + group was less likely to achieve MRD-negative complete remission post-transplant (11% vs. 42%; p