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 x 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 x 10(-7) and 1 x 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.