Risk-Stratified 2 mg/kg ATG Induction in Kidney Transplantation: Comparing Two- and Three-Dose Regimens at a Single Center.

BACKGROUND

Antithymocyte globulin (ATG), an effective induction agent in kidney transplantation; especially for high-risk recipients is associated with infection risks, hematologic toxicity, and high costs. This study assessed clinical and economic outcomes of a risk-based ATG protocol comparing 4 vs 6 mg/kg regimens.

METHODS

We conducted a single-center retrospective study of 260 kidney transplant recipients stratified by immunologic risk to receive 2 (4 mg/kg total) or 3 (6 mg/kg total) 2 mg/kg ATG doses. Outcomes included acute rejection, tacrolimus levels, and readmissions. Multivariate analysis adjusted for PRA and donor factors. Costs were estimated using standardized ATG pricing.

RESULTS

ATG dosing (2 doses for 63% of patients; 3 doses for 37%) resulted in similar biopsy-proven acute rejection rates (17.1% vs 10.6%, p = .224). However, borderline rejection was significantly higher in the 2-dose group. Time to rejection after transplant was not significantly different between the 2 groups, and tacrolimus levels were also similar. ATG dose was not an independent predictor of rejection; PRA was significant in the model adjusted for KDPI. A cost effectiveness analysis showed that the 2-dose regimen would have saved approximately $684,000 in this patient population.

CONCLUSIONS

A 2-dose ATG regimen demonstrated comparable clinical efficacy with respect to biopsy-proven rejection and short-term post-transplant outcomes, while offering substantial cost savings. Although the 2-dose group experienced significantly higher rates of borderline rejection, this did not translate into inferior clinical outcomes, suggesting these episodes may be manageable within a steroid-free program utilizing protocol biopsies. These findings support risk-adapted induction strategies but highlight the role of clinician judgment in real-world applications.