Eight-color multiparameter flow cytometry (EuroFlow-NGF) is as sensitive as next-generation sequencing in detecting minimal/measurable residual disease in autografts of patients with multiple myeloma.

The prognostic value of minimal/measurable residual disease (MRD) detection in autografts of patients with multiple myeloma (MM) in an autologous stem-cell transplantation setting has been reported. Next-generation flow (NGF) cytometry has lower sensitivity (2 × 10 -6 ) to detect MRD than next-generation sequencing (NGS) (<10 -6 ). We compared the clinical value of high-sensitivity NGF (cutoff: <10 -6 ) and NGS (cutoff: 10 -6 ) for the detection of MRD in the cryopreserved autografts of 49 patients with newly diagnosed MM. The sensitivity test using frozen/thawed autografts revealed a strong correlation among MRD levels of 5 × 10 -7 and 1 × 10 -4 ( r  = 0.9997, p  < 0.0001) when an adequate number of cells were analyzed. Autograft MRD levels determined using NGF and NGS were highly correlated ( r  = 0.811, p  < 0.0001). MRD-negative patients identified with NGF (cutoff: <10 -6 ) showed significantly longer progression-free survival (PFS) than MRD-positive patients ( p  = 0.026). The PFS of MRD-negative patients determined by NGS (cutoff: 10 -6 ) was similar to that determined by NGF. These results show that the high-sensitivity NGF method can assess MRD in frozen/thawed autografts, and its prognostic value is comparable to that of NGS.