ETD

• Multiple Myeloma
• Soluble B-cell maturation antigen

Background. The management of Multiple Myeloma (MM) is challenging due to unexpected relapses, highlighting the need for innovative disease monitoring tools. B-Cell Maturation Antigen (BCMA) is a key target in novel therapies, but its role as a soluble biomarker requires further investigation. This prospective investigation evaluates the comparative efficacy of soluble B-cell maturation antigen (sBCMA) versus free light chains (FLCs) in forecasting short-term treatment outcomes.
Methods. A cohort of 100 MM patients (40 newly diagnosed, 60 relapsed) was stratified into 5 subgroups. Serum sBCMA and FLC levels were quantified at baseline, 1 month, and 6 months post-treatment. Therapeutic response was adjudicated at 6 months via IMWG criteria.
Results. Baseline analysis revealed that sBCMA was the sole biomarker capable of significantly distinguishing between cohorts, peaking in non-transplant-eligible patients. While absolute concentrations of all parameters decreased markedly over time, only the 1-month relative reduction of sBCMA differed significantly among subgroups. Pronounced declines in all markers tracked with optimal 6-month clinical endpoints. However, multivariate ordinal logistic regression confirmed that only the 1-month sBCMA percentage drop stood as an independent predictor of therapeutic success; an sBCMA reduction of less than 50% carried a 5.444-fold higher risk of achieving inferior 6-month responses.
Conclusions. Longitudinal fluctuations in sBCMA provide a clear advantage over FLC tracking for initial risk stratification and early response evaluation. This study validates early dynamic sBCMA reduction as a rapid, autonomous measure of treatment efficacy in a real-world MM population.