Long-term outcome of azathioprine versus mycophenolate mofetil in cyclosporine-based immunosuppression in kidney transplantation: 10 Years of experience at a single center

Background: Mycophenolate mofetil (MMF) has been used worldwide as part of maintenance immunosuppression since initial large cyclosporine-based trials reported that compared with azathioprine (AZA), MMF reduced acute rejection episodes after renal transplantation. However, long-term benefits of MMF have not been established; the follow-up period of previous studies was within 5 years. The aim of this study was to compare the acute rejection rates, allograft function, and graft and patient survivals of these 2 drugs in conjunction with cyclosporine and steroids over a period of 10 years. Methods: We reviewed recipients who had undergone kidney transplantation from January 1998 to January 2002. Eighty-six patients were divided into 2 groups (MMF = 43, AZA = 43). All patients received cyclosporine and steroids concomitantly as maintenance immunosuppressive therapy. Results: Baseline characteristics were similar between the 2 groups except donor type. Multiple logistic regression analysis showed MMF therapy to reduce the acute rejection rate in the first 12 months after transplantation (relative risk [RR], 0.181; 95% confidence interval [CI], 0.035-0.936; P =.042). Cox proportional hazard analysis revealed MMF to was not associated with improved graft and patient survival. Graft function was comparable between the 2 groups over 10 years. No significant differences were observed in the incidence of serious infections or malignancy. Conclusions: Compared with AZA, MMF offered the clinical benefit of prevention of acute rejection episodes, but displayed similar effects on long-term graft and patient survivals in kidney transplant recipients undergoing cyclosporine-based immunosuppression.