Improved survival in older patients with myeloid malignancies undergoing haploidentical peripheral blood stem cell transplantation with low-dose anti-thymocyte globin (ATG)/post-cyclophosphamide (PTCy)-based regimen for graft-versus-host disease prophylaxis

Our study delved into the clinical outcomes of haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) for older patients, utilizing a novel low-dose antithymocyte globin (ATG)/post-cyclophosphamide (PTCy)-based regimen to prevent graft-versus-host disease (GVHD). We juxtaposed these outcomes with transplants from matched unrelated/sibling donors (MUD/MSD) for elderly patients with myeloid malignancies from 2016 to 2023. The study encompassed 127 patients, with 40 undergoing MUD/MSD-PBSCT and 87 receiving haplo-PBSCT. The incidences of grades II-IV and III-IV acute GVHD were similar between the two groups, the haplo-PBSCT cohort displayed a promising trend toward reduced incidence of moderate to severe chronic GVHD compared to MUD/MSD-PBSCT (8.19% vs. 23.40%, P = 0.067). The 2-year disease-free survival (74.11% vs. 59.67%, P = 0.231), overall survival (76.30% vs. 64.00%, P = 0.482) and non-relapse mortality rates (14.73% vs. 5.00%, P = 0.116) were comparable, while haplo-PBSCT exhibited higher graft-versus-host disease-free, relapse-free survival (GRFS) (68.85% vs. 46.61%, P = 0.041) and lower cumulative incidences of relapse (CIR) (11.16% vs. 31.98%, P = 0.010) compared to MUD/MSD-PBSCT. Our findings underscore the potential of haploidentical transplants using a low-dose ATG/PTCy-based regimen to yield improved GRFS and lower CIR in older patients with hematologic malignancies.