Improved post-transplant outcomes in recent years for AML patients with FLT3-ITD and wild-type NPM1: a report from the EBMT acute leukemia working party.

Abstract

Allogeneic hematopoietic cell transplantation (allo-HCT) is recommended in first complete remission (CR1) in acute myeloid leukemia (AML) patients harboring FLT3 internal tandem duplication (FLT3-ITD). We assessed changes over time in transplant characteristics and outcomes in AML patients aged 60 years and younger with a FLT3 ITD. We identified 1827 adult AML patients (median age 49 years, range 18-60) with FLT3 ITD and intermediate karyotype, allografted between 2012 and 2021 in CR1. NPM1 was mutated in 72% of patients. We compared changes over time in 688 patients transplanted between 2012 and 2016, and 1139 patients transplanted between 2017 and 2021. For patients with wild-type NPM1, the 2-year leukemia free survival (LFS) and overall survival (OS) significantly improved over time from 54% to 64% (hazard ratio [HR] =0.67; p=0.011) and from 63% to 71% (HR=0.66; p=0.021), respectively. Allo-HCT in recent years significantly reduced the cumulative incidence of relapse (CIR). For patients with NPM1 mutation, no significant changes over time were noted. In AML patients with FLT3 ITDand wild-type NPM1, we noticed a significant decrease over time in the CIR and improvement of LFS and OS, likely reflecting the efficacy of FLT-3 inhibitors, including when used as post-transplant maintenance, in this high-risk setting. On the contrary, no significant change over time was noticed in outcomes of patients harboring a FLT3 and NPM1 mutation.