Puig, NoemiContreras, Maria-TeresaAgullo, CristinaMartinez-Lopez, JoaquinOriol, AlbertBlanchard, Maria-JesusRios, RafaelMartin, JesusIñigo, Maria-BelenSureda, AnnaHernandez, Miguel-Teodorode la Rubia, JavierGonzalez-Calle, VeronicaKrsnik, IsabelCabañas, ValentinPalomera, LuisMoraleda, Jose-MariaBargay, JoanCedena, Maria-TeresaPaiva, BrunoRosiñol, LauraBlade, JoanSan Miguel, JesusLahuerta, Juan-JoseMateos, Maria-Victoria2023-05-032023-05-032022-02-07Puig N, Contreras MT, Agulló C, Martínez-López J, Oriol A, Blanchard MJ, et al. Mass spectrometry vs immunofixation for treatment monitoring in multiple myeloma. Blood Adv. 2022 Jun 14;6(11):3234-3239.http://hdl.handle.net/10668/20250Monitoring 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.enAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttps://creativecommons.org/licenses/by-nc-nd/4.0/Antibodies, MonoclonalImmunoglobulin Light ChainsTransplantation, AutologousHematopoietic Stem Cell TransplantationHumansMass SpectrometryMultiple Myelomaresearch article35157768open accessEspectrometría de masasHumanosMieloma múltipleTrasplante de células madreHematopoyéticas10.1182/bloodadvances.20210067622473-9537PMC9198943https://doi.org/10.1182/bloodadvances.2021006762https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9198943/pdf