Significance of minimal residual disease monitoring by real-time quantitative polymerase chain reaction in core binding factor acute myeloid leukemia for transplantation outcomes

Background: Despite the well-defined role of minimal residual disease (MRD) monitoring by real-time quantitative polymerase chain reaction (RT-PCR) for RUNX1/RUNX1T1 and CBFB-MYH11 transcripts in core binding factor (CBF) acute myeloid leukemia (AML) after intensive chemotherapy, there has been a paucity of data assessing the utility of MRD monitoring at and after allogeneic hematopoietic stem cell transplantation (HSCT). Methods: Patients with CBF AML who underwent HSCT in complete remission (first or second) from January 2007 through December 2018 were included in this analysis. Results: MRD by polymerase chain reaction at HSCT was assessed in 50 of 76 patients, and 44 (88%) had evidence of MRD (MRDpos). MRDpos patients had 3-year overall survival (OS) and leukemia-free survival (LFS) rates of 69.3% and 66.3%, respectively. Six MRD-negative patients had 3-year OS and LFS rates of 100% and 100%, respectively. Thirty-five of the 70 evaluable patients (50%) had a day +100 MRD assessment by RT-PCR, and 14 (40%) were MRDpos. The presence of MRD by RT-PCR on day +100 was not associated with lower estimates of LFS (75% vs 82.2%; P =.3) but was associated with a higher relapse incidence, although the difference did not reach statistical significance (27.6% vs 9.7%; P =.2). Conclusions: Durable complete remissions can be achieved in patients with CBF AML with HSCT even if they are MRDpos by RT-PCR at HSCT. The clinical impact of frequent MRD monitoring for identifying a group at high risk for early relapse and then for determining the best time point for therapeutic interventions to prevent impending relapse warrants investigation in prospectively designed clinical trials.