Reduced-intensity conditioning with fludarabine and busulfan for allogeneic hematopoietic cell transplantation in elderly or infirm patients with advanced myeloid malignancies

We report a retrospective single-center analysis of 112 consecutive patients that underwent allogeneic hematopoietic cell transplantation (HCT) after reduced-intensity conditioning (RIC) with fludarabine (FLU) and busulfan (BU) for the treatment of acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) and myeloproliferative syndrome (MPS) from 2005 to 2014. Three-year event-free survival (EFS) and overall survival (OS) were 46 and 58 %, respectively. Patients ≥60 years of age showed a similar outcome compared to younger patients (3-year OS 55 vs. 61 %, p = 0.96; 3-year EFS 46 vs. 46 %, p = 0.82). Cumulative incidence of non-relapse mortality (NRM) at 3 years adjusted for relapse as competing risk was 25 % for patients aged <60 years and 15 % for older patients (p = 0.15). Infusions of higher CD34+ blood stem cell doses were associated with a significantly better outcome in the elderly subgroup (3-year OS 82 vs. 39 %, p = 0.007). Moreover, complete donor chimerism at day +100 was associated with a significantly improved survival (3-year OS 69 vs. 23 %, p = 0.003). In conclusion, our data suggest that RIC with FLU/BU enables long-term disease-free survival even in an elderly patient population. Age has no negative impact on the outcome of allogeneic HCT, and decision for transplant should be based on disease risk and performance status rather than age alone.