Long-term toxicity of antithymocyte globulin induction may vary with choice of agent: a single-center retrospective study.

Background. Antithymocyte globulin (ATG) preparations are frequently used as induction treatment in renal transplantation, but little is known about the clinical equivalence of these different agents. We performed a retrospective, single-center study to compare the long-term clinical effects of ATG Fresenius (ATGF) and Thymoglobulin (SangStat, Fremont, CA) in renal transplant recipients. Patients and Methods. A total of 194 consecutive renal transplant recipients were included who had undergone transplantation in our center between June 1993 and April 2001 and had received ATGF or Thymoglobulin as induction treatment. Results. A total of 129 patients received ATGF and 65 patients received Thymoglobulin. Thirty patients (23%) in the ATGF group demonstrated cytomegalovirus (CMV) disease, whereas 24 patients (37%) in the Thymoglobulin group demonstrated CMV (P=0.02). Five patients (3.9%) in the ATGF group and eight patients (12.3%) in the Thymoglobulin group developed posttransplant malignancy (P=0.01). Five patients (3.9%) in the ATGF group and nine patients (13.8%) in the Thymoglobulin group died during follow-up (P=0.005). Cox regression analysis revealed that Thymoglobulin was an independent predictor of CMV disease (relative risk [RR] 2.16, confidence interval [CI] 95% [1.04-4.48]), malignancy (RR 2.16, CI 95% [1.04-4.48]), and death (RR 4.14, CI 95% [1.36-12.6]). Conclusion. In renal transplant recipients, induction therapy with Thymoglobulin seems to be associated with a significantly greater incidence of CMV disease, malignancy, and death compared with ATGF.