The AML EBMT Cytogenetic Risk Score for Acute Myeloid Leukaemia (AML) Is Prognostic for Outcomes of Allogeneic Stem Cell (HSCT)

Background: The AML EBMT Cytogenetic Risk score is a new prognostic model recently published (Canaani et al. Leukemia. 2019 Aug;33(8):1944-1952; Nagler el al. Am J Hematol. 2020 Jun 12) combining cytogenetics and FLT3ITD status for AML patients in complete remission (CR) at transplant time. The AML EBMT Cytogenetic Risk score is prognostic for leukemia-free survival (LFS), overall survival (OS), GVHD-free/relapse-free survival (GRFS) and cumulative incidence of relapse (CIR). In our centre, we frequently offer in-vitro partial T-cell depleted graft (pTDEP) for patient in CR to decrease morbidity and mortality associated with graft-versus-host disease (GvHD). Currently, The AML EBMT Cytogenetic Risk score has not been evaluated in this population. Aims: We investigate the impact of the AML EBMT Cytogenetic Risk score for 3 years OS, LFS, GRFS, CIR and NRM in a cohort with patients allografted with pTDEP graft. Methods: All consecutive ≥18 years patients who received a first allograft for AML between 2008 and 2018 with data available to determine The AML EBMT Cytogenetic Risk score in CR at transplant time were included. OS and LFS were investigated with the Kaplan-Meier method and we used the cumulative incidence estimator as defined by Fine and Gray to calculate CIR (with NRM as competing event), NRM (with relapse as competing event) and GvHD (with relapse as competing event). Results: 135 patients were included, median age at transplant time was 56 years (range: 19-74), 44% were female, median Karnofsky index was 90 (80-100). 21% of graft were from HLA identical, 57% from matched unrelated donor, 10% from mismatched unrelated donor and 12% from haploidentical donor. Stem cell source was peripheral blood in 89% and bone marrow in 11%. Partial in-vitro T-cell depletion (pTDEP) was performed in 40% of HSCT. Reduced-intensity (RIC) was performed in 62%. Median follow-up was 3.1 year (range 1.3-10 years) for living patients. Among the 135 patients, 4 (3%) were assigned in the favourable (Fav), 58 (43%) in the intermediate/FLT3wt (Int/FLT3wt), 36 (27%) in the intermediate/FLT3ITD (Int/FLT3ITD), and 37 (27%) in the adverse (adv) risk group. 3-years OS for Fav, Int/FLT3wt, Int/FLT3ITD and Adv was 75% (32-100%), 65% (52-77%), 60% (43-77%) and 28% (10-45%), respectively (p=0.033) (Fig 1A). 3-years LFS for Fav, Int/FLT3wt, Int/FLT3ITD and Adv was 75% (95%CI: 32-100%), 60% (47-73%), 49% (32-66%) and 25% (8-42%), respectively (p=0.028) (Fig 1B). 3-years GRFS for Fav,