Mild chronic graft‐versus‐host disease may alleviate poor prognosis associated with FLT3 internal tandem duplication for adult acute myeloid leukemia following allogeneic stem cell transplantation with myeloablative conditioning in first complete remission: a retrospective study

Internal tandem duplication (ITD) of the FLT3 gene (Fms‐like tyrosine kinase 3) is the most commonly found mutation in acute myeloid leukemia (AML). The significance of FLT3‐ITD at diagnosis was retrospectively estimated for allo‐HSCT (allogeneic hematopoietic stem cell transplantation) outcomes in 140 patients, median age of 38, undergoing allo‐HSCT after myeloablative conditioning in first complete remission of AML. FLT3‐ITD was detected at AML diagnosis in 42/140 (30%) of included into this study patients. At 3 years, relapse incidence (RI) following allo‐HSCT in AML patients with intermediate or normal karyotype was significantly higher in those FLT3‐ITD positive than FLT3‐ITD negative 52.9 vs. 20.4%, P = 0.002]. Additionally, patients with mild chronic graft‐versus‐host disease (cGvHD) had significantly lower RI compared to patients with moderate or severe grade cGvHD or those not experiencing cGvHD, respectively, 4.8 vs. 36.0 vs. 27.8%, P = 0.032. FLT3‐ITD was harboring a poor prognosis in AML with intermediate or normal karyotype and significantly increased risk of relapse following allo‐HSCT. It appears that allo‐HSCT does not cure patients with FLT3‐ITD, unless they develop symptoms of mild cGvHD and graft versus leukemia, which may decrease RI.