Lahuerta, Juan-JoséJiménez-Ubieto, AnaPaiva, BrunoMartínez-López, JoaquínGonzález-Medina, JoséLópez-Anglada, LucíaCedena, María-TeresaPuig, NoemiOriol, AlbertBlanchard, María-JesúsRíos, RafaelMartin, JesúsMartínez, RafaelSureda, AnnaHernández, Miguel Teodorode la Rubia, JavierKrsnik, IsabelCabañas, ValentínPalomera, LuisBargay, JoanMateos, María-VictoriaRosiñol, LauraSan Miguel, Jesús FBlade, Joan2023-01-252023-01-252019-04-22http://hdl.handle.net/10668/13863Response criteria for multiple myeloma (MM) require monoclonal protein (M-protein)-negative status on both serum immunofixation electrophoresis (sIFE) and urine (uIFE) immunofixation electrophoresis for classification of complete response (CR). However, uIFE is not always performed for sIFE-negative patients. We analyzed M-protein evaluations from 384 MM patients (excluding those with light-chain-only disease) treated in the GEM2012MENOS65 (NCT01916252) trial to determine the uIFE-positive rate in patients who became sIFE-negative posttreatment and evaluate rates of minimal residual disease (MRD)-negative status and progression-free survival (PFS) among patients achieving CR, CR but without uIFE available (uncertain CR; uCR), or very good partial response (VGPR). Among 107 patients with M-protein exclusively in serum at diagnosis who became sIFE-negative posttreatment and who had uIFE available, the uIFE-positive rate was 0%. Among 161 patients with M-protein in both serum and urine at diagnosis who became sIFE-negative posttreatment, 3 (1.8%) were uIFE positive. Among patients achieving CR vs uCR, there were no significant differences in postconsolidation MRD-negative (enAdultAgedAntineoplastic Combined Chemotherapy ProtocolsElectrophoresisFemaleHumansMaleMiddle AgedMultiple MyelomaMyeloma ProteinsRandomized Controlled Trials as TopicTreatment Outcomeresearch article31010846open access10.1182/blood.20190006711528-0020https://ashpublications.org/blood/article-pdf/133/25/2664/1557496/bloodbld2019000671.pdf