Effects of two doses of anti-T lymphocyte globulin-Fresenius given after full-match sibling stem cell transplantation in acute myeloblastic leukemia patients who underwent myeloablative fludarabine/busulfan conditioning

Abstract

Objective/background: Anti-T lymphocyte globulin Fresenius (rATG-F; ATG-Fresenius) and antithymocyte globulin (thymoglobulin), which are included in transplant protocols, are used to reduce the risk of chronic graft-versus-host disease (cGVHD) or suppress allograft rejection. Available clinical studies have been conducted in heterogenous patient populations and with different administration protocols including stem cell sources. Additionally, the pharmacokinetics of ATG is variable, and the clinically effective dose of rATG-F, in particular, is not exactly known. The aim of the study was to investigate the clinical outcomes of acute myeloid leukemia (AML) patients who underwent hemopoietic peripheral stem cell transplantation from full-matched sibling donors and given two different doses of r-ATG-F. Methods: This was a single-center, retrospective chart review conducted between July 2005 and July 2016. Sixty-nine consecutive AML patients who underwent transplant with fludarabine- and busulfan-based conditioning were included in the study. Patients in Group 1 received 15 mg/kg body weight rATG-F to 2013 (n = 46), and Group 2 received 30 mg/kg of rATG-F dose begining in 2013 to reduce to cGVHD (n = 23). Cyclosporine and methotrexate were used to treat acute GVHD (aGVHD) prophylaxis. Outcome parameters were compared between the groups. Results: Although the recommended dose r-ATG-F had led to a decrease in the cumulative incidence of cGVHD (27 [58.7%] vs. 8 [34.8%]; p =.03), it also increased the infection rate at 1 year (3 [6.5%] vs. 4 [17.4%]; p =.02). The two groups were similar in terms of engraftment time, aGVHD, relapse, nonrelapse mortality, and rATG-F-related toxicity. A Cox regression model revealed that aGVHD III–IV was associated with increased nonrelapse mortality at 1 year (hazard ratio = 18.2; 95% confidence interval, 1.667–199.255; p = <.02). No patients developed rATG-F-related severe adverse events (Common Terminology Criteria grade 4 or 5). Conclusion: Dose difference of rATG-F did not influence survival parameters; however, increasing the dose to 30 mg/kg seems to be effective for reducing cGVHD with an increase in infection rate requiring close monitoring of infections in AML patients who received myeloablative fludarabine/busulfan conditioning. © 2018 King Faisal Specialist Hospital & Research Centre