Exploring treatment options in renal transplantation: the problems of chronic allograft dysfunction and drug-related nephrotoxicity.

The immunosuppressive benefits of cyclosporine and tacrolimus in short-term and medium-term renal allograft survival are well documented. It is becoming increasingly clear that the basis of this immunosuppression, the inhibition of calcineurin, may be linked with nephrotoxicity, hypertension, hyperlipidemia, and new-onset diabetes mellitus, side effects that may lead to CRAD, death due to CVD, and late renal allograft loss. This clinical picture presents a clear need for new strategies that produce adequate immunosuppression to prevent acute rejection while simultaneously reducing the side effects associated with CNI-related therapies. Sirolimus combined with cyclosporine and tacrolimus has demonstrated an ability to reduce incidences of early acute rejection and, used as base therapy, has provided protection against acute rejection equivalent to that of cyclosporine, without the consequent nephrotoxicity associated with CNIs. In preliminary results from an ongoing clinical trial, sirolimus has been used to eliminate cyclosporine during maintenance immunosuppression, with subsequent improvements in measures of blood pressure and renal function. In addition, the antiproliferative properties of sirolimus and its ability to prevent graft vascular disease in animal studies make sirolimus a promising agent to decrease incidences of CRAD and improve long-term renal allograft survival. These findings point to a clear need to further explore both the efficacy of sirolimus immunotherapy and its long-term effects.