[Analysis of the therapeutic effect of avatinib bridged allogeneic hematopoietic stem cell transplantation on 7 cases of recurrent/refractory RUNX1-RUNX1T1 positive acute myeloid leukemia with KIT mutations].

<b>Objective:</b> To evaluate the efficacy of avatinib plus allogeneic hematopoietic stem cell transplantation (allo-HSCT) for the treatment of recurrent/refractory RUNX1-RUNX1T1 positive acute myeloid leukemia (AML) with KIT mutations. <b>Method:</b> A retrospective study was conducted on the clinical data of seven relapsed/refractory AML patients containing the RUNX1-RUNX1T1 fusion gene and KIT mutation who received afatinib plus allo-HSCT treatment at the First Affiliated Hospital of Soochow University from June 2019 to June 2023. <b>Results:</b> The seven AML patients included one male and six females with a median age of 37 (18-56) years. All seven patients had KIT mutations (five positive for D816V and two positive for D816Y) . There were two refractory patients and five relapsed patients (all of whom had bone marrow recurrence) . All patients had to complete at least one course of treatment with afatinib before transplantation. Four patients achieved complete remission (CR) after treatment with afatinib, six patients had negative KIT gene mutations, and one had a decreased KIT gene mutational burden. There were three cases of unrelated identical transplantation and four cases of haploidentical transplantation. All patients received the modified Bu/Cy pretreatment regimen. After transplantation, all patients were successfully implanted and a bone marrow examination showed CR and minimal residual disease turned negative. Five patients exhibited negative fusion genes. Two patients died from infection following transplantation. <b>Conclusion:</b> Afatinib plus allo-HSCT may be an effective and safe new treatment strategy for RUNX1-RUNX1T1 positive AML patients with KIT-D816 mutation.