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Abstract

Objectives: The optimal dose of rabbit antithymocyte globulin induction therapy in kidney transplant recipients with high immunologic risk lacks consensus. The purpose of this study was to evaluate the effect of using ideal body weight rather than total body weight for the weight-based dose calculations in this patient population. Materials and Methods: Data were retrospectively collected on 89 adult patients who received rabbit antithymocyte globulin induction therapy for high immunologic risk kidney transplant. Hospital protocol changed from the use of cumulative rabbit antithymocyte globulin doses of 7.5 mg/kg total body weight to 7.5 mg/kg ideal body weight in 2009. Patients were separated into 2 cohorts based on the amount of rabbit antithymocyte globulin (in mg/kg total body weight) received. Rate of biopsy-proven acute rejection, patient survival, and allograft function were evaluated at 90 days and 1 year after transplant. Cost of induction therapy was also evaluated. Results: Baseline demographics were predominantly similar between the 2 cohorts. No significant difference in maintenance immunosuppression was identified. Rates of biopsy-proven acute rejection at 90 days and 1 year were similar between ideal and total body weight cohorts (4.2% vs 0% at 90 days, P = .5; 8.7% vs 0% at 1 year, P = .13). Patient survival and allograft function were also similar. Median cost of rabbit antithymocyte globulin induction therapy per patient was lower in the ideal body weight cohort, but this difference was not statistically significant ($17 542 vs $19 934; P = .3). Conclusions: Our results suggest that use of ideal body weight for dose calculations of rabbit antithymocyte globulin induction therapy in high immunologic risk kidney transplant recipients at 7.5 mg/kg results in low rates of acute rejection with a safety profile similar to that shown with a total body weight dosage. Use of ideal body weight for lower cumulative doses may still need further evaluation in this patient population.

Ideal Body Weight-Based Dosing of Rabbit Antithymocyte Globulin for Cost Minimization in Kidney Transplantation

“…Unfortunately, patients were not actually dosed based on IBW and exact cumulative dose exposure was not reported. 10 Another publication compared rATG >7.5 mg/kg IBW to <7.5 mg/kg IBW, finding no difference in biopsyproven rejection rates or graft survival. This investigation was limited by its small sample size and failure to report total dose received, limiting comparability to contemporary dosing strategies.…”

“…This approach may be particularly sensible in the setting of increasing rates of obesity in the transplant population. 10 Two studies have found these strategies to yield favorable outcomes related to rejection and graft function; however they are limited by small sample sizes and lack of specific information about cumulative dose exposure. 10,11 This quality improvement study sought to evaluate posttransplant care process improvement through dose minimization of rATG using an IBW-based dosing protocol in a large cohort of kidney transplant recipients.…”