[Efficacy of Venetoclax Plus Azacitidine in Relapsed/Refractory Acute Myeloid Leukemia Patients with FLT3-ITD Mutation]

To explore the efficacy of venetoclax (VEN) plus azacitidine (AZA) in patients with FLT3-ITD mutated relapsed/refractory acute myeloid leukemia (FLT3-ITD R/R AML) and analyze the molecular genetic characteristics of the patients.

Clinical baseline characteristics and follow-up data of 16 R/R AML patients treatd with VEN plus AZA in the hematology department of Shenzhen Second People's Hospital from November 2018 to April 2021 were collected. Leukemia related genes were detected by next-generation sequencing(NGS) or PCR. The relationship between the efficacy of VEN plus AZA and molecular genetics characteristics of patients with FLT3-ITD R/R AML were analyzed.

14.3% (1/7) of the patients in FLT3-ITD group and 22.2% (2/9) of the patients in FLT3-ITD group achieved complete remission (CR)/CR with incomplete blood count recovery (CRi), respectively, with no significant difference (P=0.69). There was no significant difference in overall response rate (ORR) (CR/CRi+PR) between FLT3-ITD group and FLT3-ITD group [42.9%(3/7) vs 44.4%(4/9), P=0.95], too. The median overall survival (OS) time of FLT3-ITD patients was significantly shorter than that of FLT3-ITD patients (130 vs 300 days, respectively) (P =0.02). Co-existing mutations of FLT3-ITD and IDH1 were detected in one patient who achieved CR. Co-existing mutations of FLT3-ITD and SF3B1 were found in one patient who achieved PR. Three FLT3-ITD R/R AML patients accompanied with NPM1 mutation had no response to VEN plus AZA.

VEN plus AZA showed a certain effect on patients with FLT3-ITD R/R AML. To improve OS of the patients, bridging transplantation is need. IDH1 and SF3B1 mutations might predict that patients with FLT3-ITD R/R AML have treatment response to VEN plus AZA, while the combination of NPM1 mutation may indicate poor response.