LONGITUDINAL MONITORING OF MULTIPLE MYELOMA USING MASS SPECTROMETRY (EXENTTM ANALYZER): THREE ILLUSTRATIVE CASES

@article{berlanga2026longitudinal,
  title = {{LONGITUDINAL MONITORING OF MULTIPLE MYELOMA USING MASS SPECTROMETRY (EXENTTM ANALYZER): THREE ILLUSTRATIVE CASES}},
  author = {Oscar BERLANGA and Jane BIRTWISTLE and Syreeta ALLEN and Gemma MALIN and Gabriella LAKOS and Nohemi CABALLERO and Elyara Maria SOARES and Maria Florencia DELGADO},
  journal = {Hematology, Transfusion and Cell Therapy},
  year = {2026},
  month = oct,
  doi = {10.1016/j.htct.2026.107888},
  url = {https://doi.org/10.1016/j.htct.2026.107888},
  note = {CC BY},
}

TY  - JOUR
TI  - LONGITUDINAL MONITORING OF MULTIPLE MYELOMA USING MASS SPECTROMETRY (EXENTTM ANALYZER): THREE ILLUSTRATIVE CASES
AU  - Oscar BERLANGA
AU  - Jane BIRTWISTLE
AU  - Syreeta ALLEN
AU  - Gemma MALIN
AU  - Gabriella LAKOS
AU  - Nohemi CABALLERO
AU  - Elyara Maria SOARES
AU  - Maria Florencia DELGADO
PY  - 2026
DA  - 2026/10/23
JO  - Hematology, Transfusion and Cell Therapy
DO  - 10.1016/j.htct.2026.107888
UR  - https://doi.org/10.1016/j.htct.2026.107888
AB  - Background: Monitoring multiple myeloma (MM) relies on serum protein electrophoresis (SPEP), immunofixation electrophoresis (IFE), and serum free light chain (sFLC) analysis. However, monitoring may be challenging in patients with low-level residual disease or those receiving therapeutic monoclonal antibodies. The EXENTTM Analyzer (The Binding Site, part of Thermo Fisher Scientific) uses MALDI-TOF mass spectrometry to identify and quantify patient-specific monoclonal immunoglobulins based on their unique mass-to-charge (m/z) signatures. We described longitudinal monitoring by the EXENT systemTM in three patients with MM and compared the findings with conventional laboratory methods. Methods: Three patients with MM undergoing routine clinical follow-up were retrospectively assessed using serial serum samples. Samples were analyzed using the EXENTTM Immunoglobulin Isotypes (GAM) assay (henceforth EXENT GAM), with results compared to SPEP and sFLCs (FreeliteTMAssays, The Binding Site). EXENT GAM response categories were modelled on those from the International Myeloma Working Group. A complete response by EXENT GAM refers to absence of the monoclonal peak in follow-up samples. Results: Each case illustrated a distinct clinical scenario in which the EXENT system provided clinically relevant information beyond conventional monitoring. Case 1 was a 77-year-old, Asian female, with oligosecretory IgAλ multiple myeloma, with a baseline M-protein of 6.52 g/L measured by the EXENT system, which was below the conventional IMWG threshold for measurable serum M-protein by SPEP. The patient’s monoclonal protein was measurable by the EXENT system throughout the follow up period, demonstrating a marked reduction in monoclonal protein during treatment from 6.52 to 0.16 g/L, followed by an increase to 1.81 g/L, by the end of follow up, consistent with disease progression. Case 2 was a 76-year-old, White female, with IgGκ MM, who was treated with daratumumab. The EXENT GAM assay distinguished the patient's IgGκ monoclonal protein from the therapeutic antibody and demonstrated a reduction in M-protein from 8.21 to 4.53g/L. In subsequent assessments, the patient becomes negative by EXENT GAM, while the therapeutic antibody peak continues to be monitored throughout the follow-up. Case 3 was a 49-year-old, White male, with IgGλ MM, treated with elotuzumab. The EXENT system distinguished the patient's IgGλ monoclonal protein from the therapeutic antibody and demonstrated a reduction in M-protein from 26.89 to 1.90 g/L. Conclusions: Across all three cases, the EXENT system allowed longitudinal assessment of the baseline monoclonal protein, including in cases where SPEP became non-quantifiable or therapeutic monoclonal antibodies were present. These cases highlight the value of MALDI-TOF mass spectrometry to support longitudinal monitoring across clinically relevant monitoring scenarios.
SN  - 2531-1379
SN  - 2531-1387
ER  -