Effect Of Post-transplantation Sorafenib Maintenance In FLT3-ITD Acute Myeloid Leukemia With Different Genetic Abnormalities And Its Mechanism

Research background and aimFLT3 internal tandem duplication(ITD)positive acute myeloid leukemia(AML)has worse prognosis and higher relapse compared to those with wild type FLT3.Allogeneic hematopoietic stem cell transplantation(allo-HSCT)has improved the prognosis of FLT3-ITD AML dramatically.However,the relapse remains high even after allo-HSCT.Recent years,sorafenib maintenance therapy post-transplantation has been proved to be able to prolong survival and reduce relapse of FLT3-ITD AML patients undergoing allo-HSCT.Nonetheless,the effect of this therapy in FLT3-ITD AML patients with different genetic abnormality patterns is unclear.Moreover,the underlying mechanism for post-transplantation sorafenib maintenance therapy to improve the prognosis remains to be explored.In this study,we aim to explore the concomitant genetic abnormality pattern of FLT3-ITD AML and its influence on the effect of sorafenib maintenance post-transplantation.Furthermore,we also investigated the possible mechanism of this therapy to improve the long-term prognosis of FLT3ITD AML patients undergoing allo-HSCT.MethodsIn this study,we analyzed the gene mutation data of 330 cases with FLT3-ITD AML and revealed the mutation rate of genes and also the mutually co-occurrence and exclusivity among genes.We also did a cohort study including 613 FLT3-ITD AML cases underwent allo-HSCT to analyze the effect of sorafenib therapy in the whole cohort and in subgroups with different concomitant genetic abnormality patterns.Finally,we performed single-cell RNA sequencing(scRNA-seq)on bone marrow cells derived from 8 patients underwent allo-HSCT to reveal the difference in immune cells between patients who received sorafenib maintenance therapy post-transplantation or not.ResultsResults from gene mutation data showed that concomitant gene mutations detected in>10%patients include NPM1,TET2,DNMT3A,IDH2,WT1,ASXL1 and RUNX1.Four gene pairs including KIT-NPM1,RUNX1-NPM1,WT1-NPM1 and TET2-WT1 were significantly mutually exclusive.In the cohort study part,we found that either sorafenib maintenance therapy pretransplantation or post-transplantation was independent protective factor for overall survival(OS),relapse-free survival and relapse.Sorafenib maintenance therapy posttransplantation significantly improved OS in patients with ELN low and high genetic risks,and in both patients with FLT3-ITD allelic ratio ≥ and<0.50.As for concomitant genetic abnormalities,sorafenib maintenance therapy post-transplantation improved OS in patients with mutated NPM1,DNMT3A,EP300,triple-mutated patients and patients carrying "activated signaling" and "DNA methylation" mutations.In the analyses of scRNA-seq data.We found that patients receiving sorafenib maintenance therapy post-transplantation(sorafenib group)have higher proportion of total NK cell and CD56 dim NK cells compared to those who did not(control group).Pathway analyses showed that in the sorafenib group,pathways related to NK cell functions including graft-versus-host disease,NK cell mediated cytotoxity and oxidative phosphorylation were significantly upregulated in total NK cell and CD56 dim NK cell compared to the control group.Cell-cell communication analyses showed that compared to the control group,the communication between CD56 dim NK cells and macrophages/CD14 monocytes within many ligand-receptor pairs related to inflammation,chemokines and immune response were increased in the sorafenib group.Compared to the control group,the evolution of NK cells in the sorafenib group was also improved.ConclusionIn this study,we uncovered the concomitant genetic abnormality landscape of FLT3-ITD AML and the mutually co-occurrence and exclusivity among the mostly mutated genes.We identified the subgroups that benefitted from sorafenib maintenance therapy post-transplantation.Moreover,sorafenib maintenance post-transplantation might improve cytotoxity,cytokines secretion and evolution of NK cells via improving the communication between NK cells and monocytes/macrophages and as a result improve prognosis in FLT3-ITD AML patients.