Mass spectrometry vs immunofixation for treatment monitoring in multiple myeloma

• Published in: Blood advances Vol. 6; no. 11; pp. 3234 - 3239
• Main Authors: Puig, Noemí, Contreras, María-Teresa, Agulló, Cristina, Martínez-López, Joaquín, Oriol, Albert, Blanchard, María-Jesús, Ríos, Rafael, Martín, Jesús, Iñigo, María-Belén, Sureda, Anna, Hernández, Miguel-Teodoro, de la Rubia, Javier, González-Calle, Verónica, Krsnik, Isabel, Cabañas, Valentín, Palomera, Luis, Moraleda, José-María, Bargay, Joan, Cedena, María-Teresa, Paiva, Bruno, Rosiñol, Laura, Bladé, Joan, San Miguel, Jesús, Lahuerta, Juan-José, Mateos, María-Victoria
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 14.06.2022; American Society of Hematology
• Subjects: Antibodies, Monoclonal; Hematopoietic Stem Cell Transplantation; Humans; Immunoglobulin Light Chains; Mass Spectrometry; Multiple Myeloma - diagnosis; Multiple Myeloma - therapy; Stimulus Report; Transplantation, Autologous
• ISSN: 2473-9529; 2473-9537; 2473-9537
• DOI: 10.1182/bloodadvances.2021006762

Monitoring of the monoclonal protein (M-protein) by electrophoresis and/or immunofixation (IFE) has long been used to assess treatment response in multiple myeloma (MM). However, with the use of highly effective therapies, the M-protein becomes frequently undetectable, and more sensitive methods had to be explored. We applied IFE and mass spectrometry (EXENT&FLC-MS) in serum samples from newly diagnosed MM patients enrolled in the PETHEMA/GEM2012MENOS65 obtained at baseline (n = 223), and after induction (n = 183), autologous stem cell transplantation (n = 173), and consolidation (n = 173). At baseline, the isotypes identified with both methods fully matched in 82.1% of samples; in the rest but 2 cases, EXENT&FLC-MS provided additional information to IFE with regards to the M-protein(s). Overall, the results of EXENT&FLC-MS and IFE were concordant in >80% of cases, being most discordances due to EXENT&FLC-MS+ but IFE− cases. After consolidation, IFE was not able to discriminate 2 cohorts with different median progression-free survival (PFS), but EXENT&FLC-MS did so; furthermore, among IFE− patients, EXENT&FLC-MS identified 2 groups with significantly different median PFS (P = .0008). In conclusion, compared with IFE, EXENT&FLC-MS is more sensitive to detect the M-protein of patients with MM, both at baseline and during treatment, and provides a more accurate prediction of patients' outcome. This trial was registered at www.clinicaltrials.gov as #NCT01916252. •EXENT&FLC-MS is more sensitive than IFE in detecting the M-protein of MM patients in serum, both at baseline and during treatment monitoring.•EXENT&FLC-MS is more accurate than IFE to predict patients' outcome.