Urine Immunofixation is Not Necessary for CR Definition in Myeloma Patients with Complete M Protein Molecule

The standard definition of complete remission (CR) in multiple myeloma (MM) requires negative urine immunofixation (IF). This has been recently challenged by Ubieto et al. (Blood 2018 132:474) showing that patients with unavailable urine IF show same disease course as those negative for M protein in urine. Aim was to test if patients with negative serum IF and urine not available have the same outcomes in terms of overall survival (OS) and progression free survival (PFS) as patients with negative urine IF on real life patient´s population.