Measurable Residual Disease in Chronic Lymphocytic Leukemia: Experience in Real-Life Setting with Dry Tube Flow Cytometric Method

Abstract

Aim:Undetectable measurable residual disease (uMRD) after chemoimmunotherapy (CI) is associated longer progression-free survival (PFS) and overall survival. However, it remains to be demonstrated whether uMRD translates into survival benefit in patients treated outside of clinical trials. Pipetting-free antibody staining procedures such as dry antibody tube method can reduce process-related errors and provide a better standardization. However, there are no clinical data about this method. The aim of the study was to evaluate the impact of dry antibody tube-based MRD analysis in the management of chronic lymphocytic leukemia (CLL).Materials and Methods:We retrospectively reviewed the data of CLL patients, who were treated with CI regimens and had MRD analysis within 6 months after therapy. Forty-six patients were included in the study. MRD was assessed by multi-color flow cytometry panels with a sensitivity level of 10-4, mostly with dry tube.Results:uMRD was achieved in 30 (65.2%) of the patients. The median PFS of patients who achieved uMRD was significantly longer compared to patients who did not. Twenty-nine patients were analyzed only by dry tube throughout study period. In the patients studied with the dry tube method, the median PFS of the ones who achieved uMRD was also significantly longer than those who did not.Conclusion:Our study has indicated that flow cytometry based MRD surveillance of CLL patients in real-life setting provides prognostic information regarding PFS in accordance with clinical studies. In addition, clinical data of dry antibody panel (DuraClone RE CLB Tube) were presented for the first time.

Keywords

• measurable residual disease
• chemoimmunotherapy
• chronic lymphocytic leukemia
• flow cytometry