A comparison of porcine anti-human T lymphocyte immunoglobulin, rabbit-ATG for GVHD prophylaxis and without ATG in matched sibling donor transplantation

Introduction: Research on anti-lymphocyte globulins other than rabbit anti-thymocyte globulin (r-ATG) in prevention of graft-versus-host-disease (GVHD) following HLA-matched siblings hematopoietic stem cell transplantation (MSD-HSCT) is limited. The objective of this study is to investigate the distinct impacts of porcine anti-human T lymphocyte immunoglobulin (p-ATG) and r-ATG on outcomes of MSD-HSCT in patients with hematologic malignancies. Patients and methods: This retrospective analysis enrolled 373 consecutive patients who underwent MSD-HSCT from January 2019 to October 2023. 135 patients received r-ATG (5mg/kg) and 51 received p-ATG (30mg/kg) for GVHD prophylaxis. 187 did not receive r-ATG or p-ATG. Results: Despite early deaths, no engraftment failure occurred. In the r-ATG group, neutrophil engraftment was observed earlier, while platelet engraftment was delayed compared to other groups. Both r-ATG and p-ATG group showed protective effect on chronic graft-versus-host disease (cGVHD) (13.9 % and 29.6 % respectively vs. 43.0 % of control group at 2 years post HSCT), whereas only the r-ATG group displayed a decreased acute GVHD (aGVHD) rate (24.9 % vs. 39.8 % of control group at day 100 post HSCT). GVHD-free and relapse-free survival (GRFS) were found superior in both r-ATG and p-ATG groups (63.4 % and 56.8 % respectively vs. 37.0 % of control group at 2 years post HSCT). R-ATG was identified as an independent protective factor for aGVHD, cGVHD and GRFS in multivariate analysis. Conclusions: Our study further confirmed the role of ATG in MSD-HSCT for improving the outcomes. No evidence supported substituting r-ATG with p-ATG in achieving these effects in the study.