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

AbstractThe 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.