Prospective Randomized Controlled Trial of Rabbit Antithymocyte Globulin Compared With IL-2 Receptor Antagonist Induction Therapy in Kidney Transplantation

Objective: The aim of this study was to determine the safety and efficacy of induction with rabbit antithymocyte globulin (RATG) compared with interleukin-2 receptor antagonists in a racially diverse kidney transplant patient population under modern immunosuppression. Background: The optimal induction therapy in patients at risk for rejection, particularly black recipients, in the modern era of immunosuppression with flow cytometry-based cross-matching is unclear. Methods: This was a prospective, risk-stratified, randomized, single-center, open-label study of 200 consecutively enrolled patients in a large academic teaching center. Patients were randomized to receive either daclizumab or basiliximab versus RATG for induction in combination with tacrolimus, mycophenolate mofetil, and corticosteroids. Patients were stratified between groups to ensure equal numbers of black, retransplants, high panel reactive antibodies (PRAs) (>20%), and prolonged cold ischemic times (>24 hours) in each group. Primary outcome measure is treatment efficacy defined as the incidence of biopsy-proven acute rejection and estimated creatinine clearance. Patients were followed up for 12 months. Renal transplant recipients were included if they were adult (18 years old) and received an allograft from a deceased, living unrelated, or nonhuman leukocyte antigen identical living-related donor. Results: A total of 200 patients (n = 98 in the interleukin-2 receptor antagonists, and n = 102 in the RATG) were enrolled from February 2009 through July 2011. One-year acute rejection rates were low and similar between groups (10% in the interleukin-2 receptor antagonist group vs 6% in the RATG group; P = 0.30). Creatinine clearance was also similar between groups (interleukin-2 receptor antagonist group 56 20 mL/min per 1.73 m(2) vs RATG group 55 +/- 22 mL/min per 1.73 m(2); P = 0.73). Subanalysis of recipient race revealed that in blacks only RATG was protective against 6- and 12-month acute rejection, without an increased risk of infection. Induction did not affect rejection rates according to recipient calculated PRAs; however, RATG was associated with an increased risk of BK virus in low-PRA patients. Conclusions and Relevance: RATG induction provides improved protection against early acute rejection in black renal transplant recipients, whereas sensitized patients do not seem to demonstrate a similar benefit from this therapy. This study is registered at Clinicaltrials.gov (NCT00859131).