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
Ryota Urushihara, Naoki Takezako, Takeshi Yoroidaka, Takeshi Yamashita, Ryoichi Murata, Kenji Satou, Shinji Nakao, Hiroyuki Takamatsu
Abstract
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 ( 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.