Adoptive Immunotherapy Using Anti-Thymocyte Globulin and Reduced Intensity Total Body Irradiation; a Cost-Effective Strategy for Allogeneic Stem Cell Transplantation

Abstract

between the groups except a higher percentage of normal cytogenetics in patients with FLT3/ITD+ (p 5 0.025).Two year OS, DFS, non-relapse mortality (NRM), and relapse of cohort were 60.8%, 55.8%, 18.0% and 31.3%, respectively. Univariate analysis showed FLT3/ITD+ compared to FLT3/ITD-patients was significantly associated with inferior DFS (2 year DFS: 19% vs. 64%, p\0.0027), increased risk of relapse (1 year: 59% vs. 19%, p\0.0009), and a trend towards decreased OS (p 5 0.08). 5 of the 16 FLT3/ITD+ patients were also positive for NPM1, which did not impact outcome. Multivariate analysis using the Cox proportion hazard regression model confirmed that FLT3/ITD+ mutations independently predicted a shorter DFS (hazard ratio [HR], 3.0; 95% CI, 1.4-6.5; p 5 0.004) and increased risk of relapse (HR, 4.9; 95% CI, 2.0-12.3, p 5 0.001). Time to relapse in patients with FLT3/ITD+ was very short with 100 days cumulative risk of 45%. Conclusion: Our data suggests that allo-SCT in FLT3/ITD+ AML CR1 does not appear to overcome the poor prognostic value, and these patients remain at high risk of early relapse even after allo-SCT. While our study is limited by small size, this further illustrates the urgent need for larger prospective studies to validate the efficacy of allo-SCT in CR1 and the need to design therapy targeting FLT3/ ITD either prior to or early-post transplant to decrease relapse for this specific subgroup.