Early measurable residual disease detection post-haematopoietic stem cell transplantation in acute myeloid leukaemia.

Background: Detection of measurable residual disease (MRD) is becoming the standard of care in the prognostication of acute myeloid leukaemia post-chemotherapy, but its role in early post-haematopoietic stem cell transplantation (HSCT) is less defined. Objectives: This study aims to examine the role of MRD detection by molecular tools in early post-HSCT settings and its significance in prognostication among other clinicopathologic factors. Design: It is a retrospective cohort study. Methods: We examined MRD early post-HSCT (median: 26 days) in patients receiving allogeneic HSCT at complete remission by droplet digital PCR or next-generation sequencing targeting leukaemia-associated mutations. The effect of MRD positivity and other clinicopathologic variables on post-HSCT leukaemia-free survival (LFS), overall survival (OS) and cumulative incidence of relapse (CIR) were investigated. Results: One hundred fifty-nine patients were included, and the median follow-up time was 6 years. Early post-HSCT MRD positivity was observed in 36% patients and was associated with higher CIR (37.1% vs 13.2% at third year, Conclusion: This study demonstrated that early MRD positivity was predictive of a higher risk of relapse, and inferior LFS and OS post-HSCT. This information laid the foundation for designing MRD-guided strategies early post-HSCT to prevent haematological relapse.