multiple-myeloma

For many decades, international collaborative efforts have driven therapeutic advances in multiple myeloma (MM). The establishment of uniform response criteria by the International Myeloma Working Group (IMWG) has been pivotal for this progress, as adherence to strict definitions ensures data comparability between trials. An essential prerequisite for the use of uniform criteria is the application of standardized methods. Of particular interest herein is the assessment of minimal residual disease (MRD) by multiparametric flow cytometry (MFC). This has been incorporated into the IMWG response criteria since 2011 to enable better risk stratification of a growing number of patients reaching a complete remission and has the promise to be used both as a surrogate marker for overall and progression-free survival and to inform treatment decisions.1,2 However, in contrast to most routine diagnostic tests for response assessment in MM, this assay has until recently suffered from large interlaboratory variations in terms of sample processing and data acquisition, resulting in highly heterogeneous sensitivities. 3 To enable uniform and sensitive MFC MRD assessment between laboratories, EuroFlow has developed standardized operating procedures.4-6 Their next-generation flow method has been incorporated as the gold standard for MFC MRD measurements in the latest IMWG response criteria, which is expected to greatly improve data validity and comparability.7