The proposal arises from the increasingly pressing need to have a program of therapy for the prevention of relapse after allogeneic transplantation in patients with acute myeloid leukemia or myelodysplasia, especially if they undergo transplantation with positive minimal residual disease. These therapeutic approaches include molecular target drugs (for example, FLT-3 inhibitors when this gene lesion is present) or apoptosis inducers in combination with hypomethylating agents (for example, the combination of venetoclax and azacitidine or decitabine) or adoptive immunotherapy (for example, with infusion of donor lymphocytes).

To date, most of these therapeutic approaches are used in the phase of hematological relapse of the disease; less often they are used in the phase of persistence of minimal residual disease at the molecular level or in the phase of loss of molecular chimerism on CD34+ cells, also due to the prescribing constraints of the competent authorities (AIFA). It is believed that the collection of the Italian experience can provide important information on the use of different therapeutic platforms, in different settings. This information could be the starting point for the design of prospective and multicenter studies to be proposed in the near future.

Inclusion Criteria:

• All patients with AML and MDS who underwent allo-SCT from 2015 to 2021, who relapsed and received salvage therapy for the relapse.

Exclusion Criteria:

• Patients with a diagnosis other than AML and MDS transplanted in the same period.

Patients diagnosed with acute myeloid leukemia and myelodysplasia relapsed after allotransplantation and who received salvage therapy.