Prospective study of patient-specific markers of measurable residual disease for early detection of relapse after HSCT for myelodysplastic syndrome

Clinical relapse is a major threat after hematopoietic stem cell transplantation (HSCT) for myelodysplastic syndrome (MDS). Early detection of measurable residual disease (MRD) could enable preemptive treatment and potentially reduced relapse risk. A prospective study in four countries evaluated the association between MRD and outcomes, assessing patient-specific mutations identified with NGS and traced using ddPCR during follow-up up to two years. Relapse was preceded by positive bone marrow MRD in 42 of 44 relapses with complete data, by a median of 71 days (range 23-283). Of 137 patiens in continuous remission, 93 were consistently MRD-negative, while five were MRD-positive at last sampling. One year relapse-free survival rates after first positive MRD were 49%, 39%, and 30% using cutoff levels of 0.1%, 0.3%, and 0.5%, respectively. The authors conclude that assessment of individualized MRD using NGS and ddPCR was feasible and could be used for early detection of relapse.