Characteristics and outcome of patients with core binding factor acute myeloid leukemia and FLT3-ITD: results from an international collaborative study

Abstract

To evaluate the prognostic impact of FLT3-ITD in core-binding factor acute myeloid leukemia in an international, multicenter survey on 97 patients (52%, t(8;21)(q22;q22); 48% inv(16)(p13q22)/t(16;16)(p13;q22)). Median age was 53 (range, 19-81) years. Complete remission (CR) after anthracycline-based induction (n=86) and non-intensive therapy (n=11) was achieved in 97% and 36% of the patients. Median follow-up was 4.43 years (95%-CI, 3.35-7.39 years). Median survival after intensive and non-intensive treatment was not reached and 0.96 years, respectively. In intensively treated patients, inv(16) with trisomy 22 (n=11) was associated with a favorable 4-year relapse-free survival rate of 80% (95%-CI, 59-100%) as compared to 38% (95%-CI, 27-54%; P=0.02) in all other CBF-AML/FLT3- ITD positive patients (n=75). Overall, 24 patients underwent allogeneic hematopoietic cell transplantation (allo-HCT), 12 in first CR and 12 after relapse. Allo-HCT in first CR was not beneficial (P=0.60); however, allo-HCT seems to improve median survival in relapsed patients compared to chemotherapy (not reached versus 0.6 years; P=0.002). Excluding inv(16) with trisomy 22, our data indicate that the outcome of CBF-AML patients with FLT3-ITD seems to be inferior compared to published data on those without FLT3-ITD, suggesting that prognostically these patients should not be classified as favorable-risk. FLT3-inhibitors may improve outcome in those patients.