The impact of cytogenetic risk on the outcomes of allogeneic hematopoietic cell transplantation in patients with relapsed/refractory acute myeloid leukemia: On behalf of the acute leukemia working party ( <scp>ALWP</scp> ) of the <scp>European group for blood and marrow transplantation (EBMT)</scp>

Karyotypic analysis at time of diagnosis has an important value in determining initial response to treatment, remission duration and overall survival (OS) in acute myeloid leukemia (AML). Less is known about its value before allogeneic hematopoietic cell transplantation (allo-HCT) in patients transplanted with active disease, either relapsed or primary refractory (Rel-Ref) AML. We explored the impact of cytogenetic risk (stratification according to MRC-UK) in 2089 patients with either Ref (n = 972) or Rel AML (n = 1117) transplanted during the period 2000-2017. Overall, 154 patients had a favorable risk, 1283 had an intermediate risk and 652 had an adverse cytogenetic risk. Median follow-up was 49 months. Compared to the favorable risk group, intermediate and adverse risk patients were associated with worse leukemia-free survival and OS and also with a higher incidence of relapse. In a subgroup analysis of patients in the intermediate risk group harboring Fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD), this remained an important prognostic factor, being associated with worse outcomes. When analyzing patients according to the intensity of the conditioning regimen, no differences were observed for the main transplant outcomes. In conclusion, in patients diagnosed with AML and transplanted with active disease, karyotype remains an important prognostic factor, allowing splitting patients into different risk groups according to their cytogenetics. Similarly, FLT3-ITD mutation also remains a negative prognostic factor in this population.