Rabbit antithymocyte globulin. A 10-year experience in cardiac transplantation.

Rabbit antithymocyte globulin, a "custom-made" pan-anti-T-cell antibody produced in rabbits, is currently being evaluated in the United States and may, within several years, become approved by the Food and Drug Administration. Because we have used this agent for induction of immunosuppression for 10 years in cardiac recipients and because the results appear to be more favorable than those obtained with other agents (horse antithymocyte globulin, antilymphocyte globulin, OKT3), we have reviewed our experience. For the purpose of analysis, all non-bridge-to-transplant cardiac recipients have been divided into three groups on the basis of immunosuppression protocol: group I (March 1979 to January 1983), 28 patients treated with rabbit antithymocyte globulin, steroids, and azathioprine; group II (January 1983 to March 1985), 29 patients treated with rabbit antithymocyte globulin, cyclosporine, and steroids; and group III (March 1985 to January 1989), 98 patients treated with rabbit antithymocyte globulin, cyclosporine, steroids, and azathioprine. Actuarial data showed advantage for group III in survival rate (1 year 94%, 2 years 91%, 3 years 88%), freedom from rejection (30% free at 1 year), freedom from infection (50% free at 1 year), freedom from death from rejection (99% free at 1 year), and freedom from death from infection (97% freedom at 1 year). Actuarial survival rates and freedom from death from rejection and infection are comparable for any of our groups with contemporary published data. In the past 3 years, we have had no death from acute rejection or from posttransplant infection. Time-related rates of infection by etiologic agents have shown a significant reduction in early bacterial, viral, and nocardial infections between groups I and III. With rabbit antithymocyte globulin 200 mg intramuscularly every day for 3 days, our current protocol, T-cells are significantly reduced and local and systemic toxicity is almost unnoticeable. A progressively increasing cyclosporine dose along with rapid tapering steroid and maintenance azathioprine immunosuppressive induction appears to be the therapy of choice in cardiac transplantation.