Pretransplant MRD does not seem to affect survival in <i>NPM1</i>-mutated AML undergoing allogeneic stem cell transplantation

Whether patients with acute myeloid leukemia (AML) harboring nucleophosmin mutations (NPM1mut) and measurable residual disease (MRD) should undergo allogeneic stem cell transplantation (allo-SCT) in complete remission (CR) remains debatable. This study assessed whether bone marrow (BM) NPM1mut MRD, detected via quantitative reverse transcription polymerase chain reaction (qRT-PCR) with 10-5 sensitivity, influences allo-SCT benefit. Data from 4 German transplantation centers included 174 patients with AML NPM1mut who underwent first allo-SCT between 2011 and 2022. Among 122 patients transplanted in CR, pre-allo-SCT MRD was positive in 54%. After allo-SCT, BM MRD negativity increased from 65% (day +30) to 73% (day +100), with FMS-like tyrosine kinase 3-internal tandem duplication and ELN risk profile affecting MRD conversion at day +30. No significant difference in leukemia-free survival (LFS) or overall survival (OS) was observed based on pretransplant MRD (3-year LFS MRD positive [MRD+], 60% vs MRD negative [MRD-], 74%; hazard ratio [HR], 1.5; P = .28; 3-year OS MRD+, 68% vs MRD-, 78%; HR, 1.42; P = .39). MRD persistence and molecular relapse outcomes did not differ (P = .8). Adverse molecular risk (HR, 4.69; P = .003) and relapsed/refractory disease (HR, 2.83/3.59; P = .005/0.001) predicted poor prognosis, while posttransplant maintenance improved survival (HR, 0.48; P = .06). Our findings suggest that in patients with NPM1mut AML MRD positivity at transplant, as assessed by qRT-PCR do not experience worse posttransplant outcomes.