Clinic-Biological Features and Prognostic Significance of MGUS-Like Myeloma who underwent to Autologous Stem Cell Transplantation.

BACKGROUND

The monoclonal gammopathy of uncertain significance (MGUS)-like model classifies multiple myeloma (MM) patients into 3 groups - MGUS-like, intermediate and MM-like--based on quantification of plasma cells (PCs) and clonal PCs in bone marrow, with distinct progression-free survival (PFS). We hypothesize that this model identifies patients with different characteristics that may influence the efficacy of autologous stem cell transplantation (ASCT).

METHODS

A multicenter retrospective study was conducted including MM who underwent ASCT in the University Hospital of Salamanca between 2005 and 2023. The phenotypic profile was performed using the calculator available on the web site https://www.mgus-like.com/

RESULTS

Four hundred and fifteen patients who underwent ASCT between 2005 and 2023 were included: 39 MGUS-like (9.4%), 187 intermediate (45.1%) and 189 (45.5%) MM-like. MGUS-like patients more likely had low ISS/R-ISS, less BM infiltration, less secretory disease, less CRAB (except for lytic lesions) and had more bone-related plasmacytomas. Most patients received ASCT in the first line, with no differences in induction regimens among groups. The MGUS-like group achieved stronger responses after ASCT, defined as complete response and minimal residual disease negative (CR MRD-ve), 70.3%, than the intermediate (47.0%) and MM-like groups (40.6%). Additionally, the MGUS-like profile was identified as an independent predictor of CR MRD-ve and PFS, decreasing the likelihood of progression or death by 40% to 60% to the other phenotypic profiles.

CONCLUSION

The MGUS-like profile is a baseline-evaluable feature that identifies a subset of patients with distinct clinical behavior and may predict greater benefit from high-dose melphalan, due to the high rate of CR MRD-ve resulting in longer survival.