Post-transplantation cyclophosphamide-based haploidentical versus Atg-based unrelated donor allogeneic stem cell transplantation for patients younger than 60 years with hematological malignancies: a single-center experience of 209 patients

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is limited by availability of HLA-matched sibling donors (MSDs). The alternative use of unrelated donors (UDs) is currently challenged by haploidentical-related donors (HRDs). We retrospectively analyzed 209 consecutive patients younger than 60 years undergoing allo-HSCT from UDs (n？=？128) or HRDs (n？=？81). Cumulative incidences of grade 3–4 acute (17 vs. 2%, p？=？0.003) and 2-year moderate and severe chronic (20 vs. 2%, p？<？0.001) GVHD were significantly higher with UD. Progression-free survival (PFS) was significantly better with HRD (51 vs. 69%, p？=？0.019), without significant difference in the cumulative incidence of relapse (CIR), non-relapse mortality (NRM), and overall survival (OS). Multivariate analyses confirmed the lower risk of acute and chronic GVHD (grade 2–4, HR？=？0.43, p？=？0.005; grade 3–4, HR？=？0.20, p？=？0.017; all grades, HR？=？0.43, p？=？0.012; moderate or severe, HR？=？0.12, p？=？0.004), better PFS (HR？=？0.61, p？=？0.046), and GRFS (HR？=？0.47, p？=？0.001) with HRD. This was confirmed in match-paired analysis. In the absence of MSDs, HRD could be considered as a suitable alternative for patients younger than 60 years