Abstract： Objective:To investigate the efficacy and safety of geritinib in the treatment of acute myeloid leukemia (AML) with FLT3 mutation.Methods:The clinical data of 5 AML patients with FLT3 mutation who were diagnosed in the University of Hong Kong-Shenzhen Hospital, Shenzhen People's Hospital, Shenzhen Second People's Hospital, Shenzhen University General Hospital from March 2020 to April 2021 were retrospectively analyzed. Relapsed patients concurrently received two- or three-drug chemotherapy combined with geritinib. Blood routine was checked once a week; liver function and renal function were checked once every 2 weeks during treatment. Bone marrow puncture was performed once every 1 to 3 months to monitor the bone marrow morphology, minimal residual disease (MRD) and FLT3 mutation expression levels. The efficacy, side effects, overall survival of these patients were analyzed after treatment with geritinib.Results:The white blood cell was increased in all the 5 patients at the initial diagnosis. FLT3 mutations analysis showed FLT3-internal tandem duplication (ITD) (3 cases) and FLT-3 tyrosine-kinase domain (TKD) (2 cases). Among 5 patients, 1 patient was relapse-free with maintenance therapy of oral geritinib after hematological stem cell transplantation (HSCT) for 60 days; among other 4 relapsed and refractory patients, 1 female patient after pregnancy relapsed after transplantation and then achieved complete remission followed by the maintenance therapy with geritinib after oral geritinib, 1 16-year-old patient achieved treatment outcome close to the complete remission after treatment with geritinib, 1 patient achieved complete remission after treatment with geritinib, and then underwent haplo-HSCT followed by the maintenance therapy with geritinib and the other 1 relapsed patient achieved complete remission after treatment with geritinib. After transplantation, 3 patients receiving maintenance treatment of geritinib did not relapse. The main side effects included anemia, decreased neutrophil count, rash, and increased aminotransferase. The median follow-up time of 5 patients was 15 months (6-20 months). All 5 cases survived until the last follow-up in November 2021 and 4 patients were disease-free.Conclusions:Relapsed and refractory AML patients with FLT3 mutation can achieve complete remission after treatment with geritinib and get a chance for transplantation. Geritinib may reduce the risk of recurrence after transplantation and improve survival rate. No serious side effects occur in geritinib treatment.