FLT3-ITD POSITIVITY IN AML; CASE SERIES

Abstract

Objective: Diagnosis of AML requires additional procedures, including pathological examination, immunophenotyping, cytogenetic examination, and molecular diagnosis. The determination of the specific cytogenetic abnormality is important for the selection of appropriate treatment and prognostic analysis.The 2 most common mutations of the FLT3 gene are FLT3-ITD and FLT3-D835. Here, we will present FLT3-ITD positive AML cases admitted to our clinic between 2019-2021. Case report: We have 5 cases of AML FLT3-ITD heterozygous. In all our cases, Midastaurin was given with 7+3 chemotherapy (CT) in the initial treatment. While 1 of our cases went into remission, the other 4 relapsed. All of the patients who relapsed were given FLAG CT, no remission was achieved and they were switched to ADE CT. Remission was achieved in 2 of 4 patients, 2 of them were refractory. One patient was given gilteritinib. HSCT was performed in 2 patients. While 2 of our patients are dead, 2 of them are in remission and 1 of our patients is still under treatment. Results: FLT3 gene mutations are strongly associated with leukocytosis and poor prognosis in patients with AML(1-3). Patients with any of these mutations have a higher risk of recurrence and a lower survival rate3. All of our patients had leukocytosis at the time of diagnosis. Four of our patients relapsed and all of these patients were refractory to chemotherapy. Our patients who were refractory to treatment had a high mortality rate (50%) and a lower survival time (8-12 months). Conclusion: FLT3 signaling inhibitors have been used both alone and in combination to improve clinical outcomes in patients with AML with FLT3 mutations. While inhibitor monotherapy provides clinical response, its efficacy is usually temporary and resistance develops rapidly. Various combination therapies are used to enhance efficacy and prevent or overcome resistance. More studies are needed to evaluate its efficacy and explain the development of resistance.