Background: A prospective clinical trial was undertaken to compare the efficacy of tacrolimus (FK 506) versus cyclosporine as the primary immunosuppressive agent after lung transplantation.
Methods: Between October 1991 and May 1994, 133 single-lung and bilateral-lung recipients were randomized to receive either cyclosporine (n = 67) or tacrolimus (n = 66). The two groups were similar in age, sex, and underlying disease.
Results: One-year and 2-year survival rates were similar in the two groups, although the trend was toward increased survival with tacrolimus. Acute rejection episodes per 100 patient-days were fewer (p = 0.07) in the tacrolimus group (0.85) than in the cyclosporine group (1.09). Obliterative bronchiolitis developed in significantly fewer patients in the tacrolimus group (21.7%) compared with the cyclosporine group (38%) (p = 0.025), and there was greater freedom from obliterative bronchiolitis over time for patients receiving tacrolimus (p < 0.03). Significantly more cyclosporine-treated patients (n = 13) required crossover to tacrolimus than tacrolimus-treated patients to cyclosporine (n = 2) (p = 0.02). The switch to tacrolimus controlled persistent acute rejection in 6 of 9 patients. The overall incidence of infections was similar in the two groups, although bacterial infections were more common with cyclosporine (p = 0.0375), whereas the risk of fungal infection was higher with tacrolimus (p < 0.05).
Conclusions: This trial demonstrates the advantage of tacrolimus in reducing the risk of obliterative bronchiolitis, the most important cause of long-term morbidity and mortality after lung transplantation.