Clinical outcomes of three haploidentical transplantation protocols for hematologic malignancies based on data from the Chinese Bone Marrow Transplantation Registry Group

This study aimed to demonstrate the clinical outcomes of granulocyte colony-stimulating factor (G-CSF)/antithymocyte globulin (ATG), posttransplantation cyclophosphamide (PTCy) and PTCy combined with low-dose ATG (PTCy with ATGlow)-based haploidentical transplantation protocols in patients with hematologic malignancies. The comparisons were conducted via propensity score matching (PSM) analysis to balance the basic characteristics among different groups and were based on the transplantation data reported to the Chinese Bone Marrow Transplantation Registry Group (CBMTRG) from January 2020 to December 2022. For each patient in the PTCy or PTCy with ATGlow group, patients (at a 1:2 ratio) from the G-CSF/ATG group were selected. In total, the PTCy group (N=122) was matched with the G-CSF/ATG group 1 (N=230), and the PTCy+ATGlow group (N=123) was matched with the G-CSF/ATG group 2 (N=226). Compared with those in the PTCy group, the incidences of 28- day neutrophil engraftment (P=0.005), 100-day platelet engraftment (P=0.002), median time to neutrophil engraftment (P<0.001) and platelet engraftment (P=0.011) were significantly greater in the G-CSF/ATG group. No significant differences were observed in acute graft-versus-host disease (aGVHD) incidence or relapse incidence. In addition, patients in the G-CSF/ ATG group had lower non-relapse mortality (NRM; P<0.001), better 3-year overall survival (OS; P<0.001) and leukemia-free survival (P<0.001) rates than those in the PTCy group. Similarly, the G-CSF/ATG group achieved lower NRM (P<0.001) and better 3-year leukemia-free survival (P=0.002) than the PTCy+ATGlow group. In conclusion, G-CSF/ATG-based haplo-HSCT may be a preferential choice for the Chinese population with hematologic malignancies. In the future, a randomized controlled study is needed for further confirmation.