Allogeneic hematopoietic stem cell transplantation to improve survival in acute myeloid leukemia patients with FLT3 internal tandem duplication.
e17014 Background: Fms-like tyrosine kinase (FLT3) gene with internal tandem duplication (ITD) is a poor prognostic factor in patients with acute myeloid leukemia (AML). Allogeneic hematopoietic stem cell transplantation (HSCT) is considered as an effective treatment for AML patients with poor risk. However, the efficacy of allogenic HSCT in the treatment of AML patients with FLT3-ITD was not clear. Methods: A total of 122 patients, who were newly diagnosed as de novo AML and received intensive chemotherapy at China Medical University Hospital between 2003 January and 2010 December, were retrospectively analyzed. At diagnosis, all patients received French-American-British (FAB) classification, cytogenetic analyses and immunophenotyping. The HSCT was performed on the basis of the consensus of the hematologists in this institute, mainly according to the two factors: unfavorable karyotype and suitable donor availability. The FLT3-ITD was detected by polymerase chain reaction and confirmed by direct sequencing. The Cox proportional hazards regression analysis was used to estimate the hazards ratios of the overall survival and corresponding 95% confidence interval (CI) for various combinations of FLT3-ITD and HSCT status. Results: An FLT3-ITD was detected in 34 patients (27.9%). The allogeneic HSCT was performed in 39 patients; 29 patients with wild type (wt)-FLT3 and 10 patients with FLT3-ITD. The number of death/number of patients (medium overall survival) of wt-FLT3/HSCT(+), wt-FLT3/HSCT(-), FLT3-ITD/HSCT(+) and FLT3-ITD/HSCT(-) was 12/29 (53.4 months), 25/59 (40.7 months), 3/10 (medium not reached) and 17/24 (12.0 months), respectively (p=0.014). Comparing with wt-FLT3/HSCT(-) patients, the hazard ratio (95% CI) of overall survival for wt-FLT3/HSCT(+), FLT3-ITD/HSCT(+) and FLT3-ITD/HSCT(-) was 1.39 (0.61-3.18), 0.40 (0.11-1.49), and 3.57 (1.58-8.09), respectively, after adjustment of age, sex, WBC, LDH, karyotype and FAB classification. Conclusions: AML patients without FLT3-ITD had better survival than those with FLT3-ITD regardless of the allogeneic-HSCT. The allogeneic HSCT may improve overall survival in AML patients with FLT3-ITD.