Comparing Two Types of Rabbit ATG prior to Reduced Intensity Conditioning Allogeneic Hematopoietic SCT for Hematologic Malignancies

Different rabbit polyclonal antilymphocyte globulins (ATGs) are used in allogeneic hematopoietic stem cell transplantation (alloHSCT) to prevent graft-versus-host disease (GvHD). We compared 2 different ATGs in alloHSCT after reduced intensity conditioning (RIC) for hematological malignancies. We reviewed 30 alloHSCT for hematologic malignancies performed between 2007 and 2010 with fludarabine and i.v. busulfan as conditioning regimen. Patients alternatingly received Thymoglobulin or ATG-F. Median followup was 3.3 (2.5–4.5) years. Adverse events appeared to occur more frequently during Thymoglobulin infusion than during ATG-F infusion but without statistical significance (P = 0.14). There were also no differences in 3-year overall survival (OS), disease-free survival (DFS), relapse incidence, and transplant related mortality (TRM) in the Thymoglobulin versus ATG-F group: 45.7% versus 46.7%, 40% versus 33.7%, 40% versus 33.3%, and 20% versus 33.3%. The same held for graft failure, rejection, infectious complications, immune reconstitution, and acute or chronic GvHD. In patients transplanted for hematologic malignancies after RIC, the use of Thymoglobulin is comparable to that of ATG-F in all the aspects evaluated in the study. However due to the small number of patients in each group we cannot exclude a possible difference that may exist.