ASSESSMENT OF RABBIT ANTITHYMOCYTE GLOBULIN DOSING AND CLINICAL OUTCOMES IN KIDNEY TRANSPLANTATION

Heather S. Snyder, Pharm.D., BCPS, Vinaya Rao, M.D., Amy G. Krauss, Pharm.D., BCPS, Alison L. Apple, M.S., D.Ph., Dagny L. Ulrich, Ph.D. and *Benjamin T. Duhart, Jr., M.S., Pharm.D.

ABSTRACT

Purpose: Optimal dosing of rabbit antithymocyte globulin (rATG) remains undefined and varies between transplant centers. Previously the Methodist University Hospital Transplant Institute (MUHTI) based rATG dosing on kidney graft function (GF) following transplantation, but now utilizes risk stratification (RS) to guide dosing. The study aim was to evaluate outcomes of the RS dosing protocol in kidney transplant recipients as compared to the GF protocol. Methods: A retrospective chart review was done to identify adult patients who underwent single-organ kidney transplantation at the MUHTI and received rATG induction using the GF or RS protocol. The following 1 year outcomes were compared between groups: mean cumulative rATG induction dose, SCr and eGFR, patient and graft survival, episodes of biopsy-proven acute rejection, and infection with BK Polyoma virus and/or cytomegalovirus. Fisher’s exact test was used to analyze categorical variables and student’s t-test was used for continuous variables. A Kaplan-Meier analysis was used to compare patient and graft survival. Results: Of the 100 patients studied, 50 were dosed under the GF protocol and 50 were dosed using the RS protocol. The mean cumulative rATG dose in the GF group was 7.4 ± 2 mg/kg compared to 5.4 ± 1 mg/kg in the RS group (p<0.05). At 1 year renal function was significantly better in the RS group versus the GF group (p<0.05) and patient and graft survival were similar between groups p>0.05). There was a higher incidence of acute rejection in the RS group (14%) versus the GF group (8%); however, this difference was not statistically significant. The incidence of infection with BK Polyoma virus and cytomegalovirus were similar between groups (p>0.05). Conclusion: The RS dosing protocol for rATG improved renal outcomes without compromising patient or graft survival and led to a decrease in the mean cumulative rATG dose in kidney transplant recipients.

Keywords: Rabbit antithymocyte globulin (rATG), risk stratification, kidney transplant this study was presented at the ACCP Annual Meeting, Albuquerque, NM, October 13-16, 2013.