Outcomes of Patients with FLT3 Positive Acute Myeloid Leukaemia; an Experience from a Tertiary Care Hospital in Karachi, Pakistan

INTRODUCTION: Molecular genetic abnormalities in acute myeloid leukaemia (AML) are essential for disease diagnosis and determining prognosis and clinical course. Mutations in FLT3 and nucleophosmin (NPM) genes are the most frequent genetic abnormalities, which are also known to impact disease outcomes. FLT3 mutations have been identified in approximately 30% of de novo AML patients and are associated with poor prognoses. This study aimed to determine the response to induction chemotherapy, overall survival (OS) and relapse rate (RR) in patients with FLT3-positive AML. MATERIALS AND METHODS: In this study, a retrospective analysis was performed of 75 newly diagnosed patients with AML registered between January 2015 and July 2022. Patient demographics and clinical-haematological parameters were noted and molecular analysis for FLT3 ITD/TKD and NPM mutations was performed. All the patients received standard induction chemotherapy and their response to treatment, OS and RR were assessed. RESULTS: A total of 75 cases of AML were analysed. The mean age of the sample was 34.9 years, of which 65.3% were males and 34.7% were females. The patients were stratified into two groups: Those who were positive for FLT3 while negative for NPM (FLT3+/NPM-), representing 17.3% and those who were negative for both FLT3 and NPM (FLT3-/NPM-), representing 82.7% of cases. On day 28 post-induction, the complete remission rate was 69.2% in the FLT3 positive group and 77.4% in the FLT3 negative group. In the FLT3+/NPM- group, 55.6% of cases who were in remission at day 28 subsequently relapsed, compared to 50.0% of FLT3-/NPM- cases. The overall median survival time for the cohort and FLT3+ group was 1467 days, while that of the FLT3-group could not be estimated due to the very high survival rate. CONCLUSION: No significant differences in outcomes were observed in patients who were FLT3 positive compared to those who were FLT3 negative.