Adults age ≥ 18 with FLT3-ITD+ AML in CR1 or CR2 after HLA-matched allo-HSCT with donor CD3 chimerism ≥ 50% and adequate blood counts: ANC > 1000, PLT > 50,000. Recent active CNS leukemic involvement or active grade ≥2 GVHD were exclusionary. Here, FLT3 is linked to acute myeloid leukemia.