Role of Allogeneic Hematopoietic Stem Cell Transplantation for None Remission / Advanced Acute Myeloid Leukemia with Flt3-Itd Mutations: Outcomes of 15 Newly Diagnosed Patients from a Single Institution

Backgrouds: Acute myelogenous leukemia (AML) patients with FLT3-ITD mutations have an inferior survival compared to AML patients with wild-type (WT) FLT3, primarily because of an increased relapse rate. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) represents a postremission therapy that is effective at reducing the risk of relapse for many cases of poor-risk AML. Whether or not allo-HSCT can improve outcomes for patients with none remission/advanced FLT3-ITD mutation AML is not known.

Objective: To compare the effect of allo-HSCT between none remission/advanced FLT3-ITD positive AML and other none remission/advanced AML excluding FLT3-ITD mutations.

Patients and methods: We analyzed 49 patients who underwent allo-HSCT with a diagnosis of none remission/advanced AML on FLT3-ITD mutations between February 2012 and Apiril 2014. Fifteen patients were FLT3-ITD positive and 24 were FLT3-ITD negative. Transplantations were performed in none remission/advanced status after myeloablative conditioning or intensified conditoning.

Results: Patient’s characteristics were similar in the two groups, including leukocyte count at diagnosis, interval from CR to transplant, disease status, donor type, stem cell resource, prepare regimens, and graft versus host disease (GVHD) prophylactic protocols. All patients achieved hematopoietic engraftment. The time to neutrophil and platelet engraftment was similar between the two groups. The incidences of acute GVHD and chronic GVHD were comparable between the two groups. At 2 year after transplantation, cumulative relapse incidence (33.3% ± 14.9% v 18.5% ± 7.7%; P =0.335) and disease-free survival (DFS) were not different (51.9% ± 15% v 61.4% ± 8.9%; P =0.749) in FLT3/ITD-positive compared with FLT3/ITD-negative patients. The overall survival between the two groups was also similar (57.0% ± 14.8% v 62.1% ± 9.3%; P =0.834).

Conclusions: FLT3-ITD didn’t affect the outcome of HSCT for none remission/advanced patients in the same direction it does after chemotherapy; and more than half of the patients harboring this mutation who received transplants were alive and disease free at 2 years.