Comparative study of porcine anti-human lymphocyte immunoglobulin and rabbit anti-human thymocyte immunoglobulin as a first-line treatment of acquired severe aplastic anemia

Porcine anti-human lymphocyte immunoglobulin (pALG) and rabbit anti-human thymocyte immunoglobulin (rATG) are the only two ATGs for severe aplastic anemia (SAA) treatment in China. 148 treatment-naïve SAA patients who received ATG combined with cyclosporine A (CsA) therapy were analysed retrospectively. The patients were divided into a pALG group (n = 114) and a rATG group (n = 34). After three months, the pALG and rATG groups had an overall response (OR) of 65.8% and 44.1%, respectively (P = 0.023); after six months, the OR reached 74.6% and 64.7%, respectively (P = 0.361). The pALG group had markedly better time-related efficacy than the rATG group (P = 0.03). The overall survival (OS) and event-free survival (EFS) between groups had no significant difference (P > 0.1). The pALG and rATG groups did not significantly differ in terms of recurrence (8.8% vs. 5.9%, P = 0.734) or PNH clonal transformation (5.3% vs. 2.9%, P = 1.000), whereas a significant difference was found in the incidence of MDS/AML transformation (2.6% vs. 11.8%, P = 0.049). We found that pALG achieved a better time-related efficacy than rATG for the treatment of SAA; nonetheless, no significant difference in the OS or EFS of pALG compared with rATG.