Effectiveness of In Vivo T-Cell Depleted Regimen Containing Porcine Antilymphocyte Globulin and Rabbit Antithymocyte Globulin in Preventing Acute Gvhd after Haploid Hematopoietic Stem Cell Transplantation
Authors: Xu Ziwei , Zhou Xi , Wang Huafang 
Published: December 2023

Objective To compare the clinical efficacy of porcine antilymphocyte globulin (p-ALG) and rabbit antithymocyte globulin (r-ATG) in the treatment of hematologic malignancies using haploid hematopoietic stem cell transplantation (haplo- HSCT), this study was conducted.

Methods This was a single center retrospective analysis of 178 subjects who received haplo-HSCT with p-ALG or r-ATG from January 2020 to December 2022. The patients were divided into three groups according to the doses of p-ALG or r-ATG used in the conditioning regimens. The study evaluated and compared the occurrence of early fever, graft versus host disease (GVHD), infection, and survival among the three groups of patients.

Results A total of 178 patients were enrolled in the study with a median age of 30 (14-61) years, including 95 men and 83 women. The median follow-up time post-transplantation was 20.1 (1.7-36.9) months. The study included 57 patients in the p-ALG 75mg/kg group, 49 patients in the p-ALG 90mg/kg group, and 72 patients in the r-ATG 7.5mg/kg group, respectively. The incidences of neutrophil and platelet engraftment, respectively, were 100%,93.5%, and 91.3% (p=0.133); 100%, 93.6%, 90.3% (p=0.033) in P-ALG 75mg/kg, P-ALG 90mg/kg and r-ATG 7.5mg/kg. The median time to neutrophil engraftment was 11 days for the P-ALG 75mg/kg group, 12 days for the P-ALG 90mg/kg group, and 12 days for the r-ATG 7.5mg/kg group (p=0.133). The median time to platelet engraftment was 12 days for the P-ALG 75mg/kg group, 14 days for the P-ALG 90mg/kg group, and 13 days for the r-ATG 7.5mg/kg group (p=0.033). In the p-ALG 75mg/kg, p-ALG 90mg/kg, and r-ATG 7.5mg/kg groups, 16 patients (28.1%), 24 patients (49.0%) and 35 patients (48.6%) developed fever within 14 days after transplantation, respectively. Cytokine release syndrome was found to be the most common cause of fever. The incidence of grades Ⅱ-Ⅳ acute GVHD (aGVHD) and grades Ⅲ-Ⅳ aGVHD, respectively, were 15.8%, 12.2%, and 12.5% (p=0.853); 5.3%, 2.0%, and 5.6% (p=0.523) in P-ALG 75mg/kg, P-ALG 90mg/kg and r-ATG 7.5mg/kg. The cumulative incidence of chronic GVHD at 1 year was 14.0%, 10.2%, and 15.3% (p=0.731) in the three groups. 43.9%, 71.4%, and 61.1% of patients in the p-ALG 75mg/kg, p-ALG 90mg/kg and r-ATG 7.5mg/kg groups, respectively, experienced at least one infection within 1 year after haplo-HSCT (p=0.0.13). Notably, the CMV infection rate in the p-ALG 75mg/kg group was significantly lower than in the p-ALG 90mg/kg and r-ATG 7.5mg/kg groups. The 2-year overall survival (OS) rates of p-ALG 75mg/kg, p-ALG 90mg/kg and r-ATG 7.5mg/kg groups were 78.2%, 70.6%, and 72.3% (p=0.491). The cumulative incidence of 2-year relapse were 33.0%, 29.8%, and 30.0% (p=0.834).

ConclusionsCompared with r-ATG group, the p-ALG 75mg/kg group showed a lower incidence of infection. However, there were no significant differences between the two groups in terms of the incidence of grades Ⅱ-Ⅳ aGVHD, 2-year overall survival (OS), and 2-year cumulative incidence of relapse. p-ALG (75mg/kg) has a comparable effect on the prevention of GVHD after haplo-HSCT with a lower incidence of infection.

Keywords: Porcine antilymphocyte globulin; Rabbit antithymocyte Globulin; Haploidentical hematopoietic cell transplantation; Graft versus host disease; Infection