Study to Assess an Interphase Cycle With Flotetuzumab.

Rate of CR/CRi without MRD defined as MRD 0.1% by flowcytometry or undetectable mutant NPM1 by qPCR after 1 cycle of flotetuzumab

Patients who have measurable residual disease (MRDpos, defined as MRD 0.1% by flowcytometry
 or detectable mutant Nucleophosmin 1 (NPM1) by quantitative polymerase chain reaction (qPCR)
 after two cycles of intensive chemotherapy) prior to start conditioning for an allogeneic
 Hematopoietic Cell Transplantation (HCT) have a very high risk of relapse after
 transplantation. Important questions in the field are whether patients with MRD after
 intensive chemotherapy can be converted to MRD negativity (i.e. undetectable MRD, MRDneg) and
 whether this conversion impacts on the relapse rate after transplantation. This trial aims to
 develop effective interphase treatment for patients in morphological complete remission
 (CR) with MRD after at least 2 cycles of intensive chemotherapy and prior to start
 conditioning for an allogeneic HCT. Flotetuzumab, a bispecific antibody-based molecule
 against CD3 and CD123 in a dual-affinity re-targeting antibody (DART®) format is a new
 treatment modality based on immunomodulation. The rationale to use flotetuzumab in this study
 is: 1) its antileukemic activity reported in R/R AML; 2) its limited extra-medullary (i.e.
 tissue) toxicity; and 3) its short halflife.