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

Abstract

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 (<i>r</i> = 0.9997, <i>p</i> < 0.0001) when an adequate number of cells were analyzed. Autograft MRD levels determined using NGF and NGS were highly correlated (<i>r</i> = 0.811, <i>p</i> < 0.0001). MRD-negative patients identified with NGF (cutoff: <10^-6) showed significantly longer progression-free survival (PFS) than MRD-positive patients (<i>p</i> = 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.