MRD and Biomarkers

Category: MRD and Biomarkers

Comparative Evaluation of Advanced Serum-Based Techniques for the Sensitive Detection of Monoclonal Proteins in Multiple Myeloma – A Pilot Study

(PA-176) Comparative Evaluation of Advanced Serum-Based Techniques for the Sensitive Detection of Monoclonal Proteins in Multiple Myeloma – A Pilot Study

Thursday, September 18, 2025

Rudolf Kupcik

Research Fellow
Biomedical Research Centre, University Hospital Hradec Kralove

Introduction: Multiple myeloma (MM) is a plasma cell malignancy characterized by the production of monoclonal immunoglobulins (mAbs). Effective monitoring of measurable residual disease (MRD) and emerging clonal populations is essential for disease management but remains limited by the invasiveness and infrequency of bone marrow examinations. To address these limitations, novel serum-based techniques have been developed and we conducted their comparative evaluation - including MALDI-TOF mass spectrometry, our novel in-house method named MQ-Sense and high-resolution LC-MS targeting clonotypic peptides of immunoglobulins.

Methods:   A cohort of ≥15 serum samples from MM patients or samples artificially spiked with monoclonal antibodies in a polyclonal serum background was analyzed. The performance of MALDI-TOF, represented by the EXENT System (Binding Site), and our newly developed MQ-Sense method—based on affinity-based isolation and HPLC detection of antibodies—was benchmarked to conventional immunofixation electrophoresis (IFE). Selected samples were further analyzed using a high-resolution nanoLC-MS/MS workflow targeting specific peptides derived from myeloma cell DNA or known sequence of standards. Each method was evaluated for analytical sensitivity, M-protein classification, and the ability to distinguish therapeutic mAbs.

Results:   IFE exhibited limited sensitivity, particularly for low-abundance monoclonal proteins e.g. post-treatment samples. Both MALDI-TOF and MQ-Sense demonstrated improved sensitivity. MQ-Sense achieved very low limit of detection (LOD) of ≤30 mg·L⁻¹ in polyclonal backgrounds. It also showed capability to differentiate therapeutic mAbs as compared to IFE and MALDI-TOF. Targeted LC-MS/MS significantly have even more sensitivity (LOD ≤1 mg·L⁻¹), enabling precise detection and longitudinal monitoring of individual clonal populations but is known for limited ability of detection newly emerging subclone. This drawback can be further improved with combination with MQ-Sense, rather than IFE, that had suboptimal LOD (175 mg·L⁻¹). The performance of MQ-Sense is comparable to MALDI-TOF, but it is more cost-effective. MALDI-TOF systems (such as EXENT) are similarly priced to a full nanoLC-MS system used for detecting clonotypic peptides.

Conclusions:

This pilot study demonstrates that MQ-Sense offers enhanced sensitivity and specificity for serum-based detection of M-proteins in MM. Compared to conventional IFE, MQ-Sense serves as a robust intermediate method and, when combined with high-resolution LC-MS/MS, enables complex and non-invasive clonal monitoring. These findings support the implementation of advanced serum-based workflows for improved MRD assessment and disease surveillance in MM.

Supported by Ministry of Health of the Czech Republic, grant nr. NW24-03-00347.