Salvage therapy using FLT3 inhibitors may improve long-term outcome of relapsed or refractory AML in patients with FLT3-ITD

To determine the long-term efficacy of FLT3 inhibitors (FLT3i) in the salvage setting for relapsed and refractory (rel/ref) acute myeloid leukemia (AML) with FLT3 internal tandem duplication (AML FLT3-ITD), we conducted a retrospective study of 120 patients with rel/ref AML FLT3-ITD who received salvage therapy with either FLT3i-containing regimen (FLT3i group, N=45) or conventional cytotoxic regimen (conventional group, N=75). The median overall survival (OS) after the first salvage in the FLT3i group was 6 center dot 9 vs. 4 center dot 6months in the conventional group (P=0 center dot 17). The OS was better in the FLT3i group among patients with initial complete remission (CR) duration 12months or with primary refractory disease (6 center dot 9 vs. 3 center dot 7months; P<0 center dot 01). The OS was better when FLT3i was combined with cytotoxic agents versus monotherapy (17 vs. 4 center dot 8months; P=0 center dot 017). Multivariate analysis revealed that the use of FLT3i was an independent predictor of OS (hazard ratio 0 center dot 58; 95% confidence interval, 0 center dot 380 center dot 88). Incorporating FLT3i into salvage strategies may improve long-term outcome of patients with AML FLT3-ITD. Prospective studies to validate this conclusion are warranted.