Addition of the Anti-CD33 Monoclonal Antibody Mylotarg to Fludarabine/High Dose Cytarabine - Based Induction Significantly Improves Outcome in Patient Affected By FLT3-ITD Positive Cytogenetically Normal Acute Myeloid Leukemia

▪ Background: The addition of the anti-CD33 targeting antibody Mylotarg (MY) to conventional “3+7” induction has been shown to improve the outcome of patients affected by acute myeloid leukemia (AML) without adverse cytogenetic alterations. Early reports suggested that MY was particularly effective among low risk patients, such as core binding factor AML, particularly if included in a high dose cytarabine-based induction therapy. The role of MY for intermediate risk patients appears to be less clear. Cytogenetically defined intermediate risk patients may be further stratified considering two frequent molecular aberrations: FLT3 “internal tandem duplication” (FLT3-ITD) mutation, associated with poor prognosis and NPM1 mutation (NPM1-mut), associated with a good prognosis. The concomitant presence of NPM1-mutpartially overcomes the negative prognostic impact of FLT3-ITD, which is also modulated by FLT3-ITD/wild type allelic ratio. NPM1 and FLT3 mutational status assessment is strongly recommended for risk stratification at diagnosis by the last ELN 2017 guidelines. Aims: To investigate the efficacy of MY added to an intensive fludarabine, high dose cytarabine and Idarubicin-based induction regimen (FLAI) as frontline treatment for younger (