Comparative Study of Tacrolimus and Rapamycin to Evaluate the Renal Function in Patients Older Than 50 Years, Receptors of a Kidney From a Donor Older Than 55 Years in a Mycophenolate Mofetil and Daclizumab Immunosuppressor Regime

The study population characteristics raise the need to establish a treatment regime that assures suitable intensity immunosuppression to avoid the appearance of rejection episodes, but minimizes the doses to prevent over-immunosuppression in a population with a theoretic minor immune response.

On the other hand, the delay in the introduction of calcineurin inhibitors will prevent increasing the risk of early graft dysfunction allowing the highest post-transplant renal recovery in organs with less operative mass and greater sensibility to the nephrotoxic effect of these drugs.

The results of several studies confirm the goodness of regimes that include low doses of calcineurin inhibitors, delay their introduction or avoid them.

Nevertheless, although it is standard practice to evaluate the effectiveness of the regimes for a time to assure, with certainty, the response to the treatments, these follow-ups are still relatively short to assure the efficacy for a long-term study and to detect the problems. The studies with a high number of patients and long follow-up periods are difficult, so several authors have proposed different alternatives of control in a short-term study that could be useful as surrogate markers or predictive efficacy variables for the long term.

If the drug or study regime is efficient, the observed change after the transplantation surgery will have to be fast and objective. The increase of serum creatinine between 6 and 12 months post-transplant is a reliable marker of graft failure risk, and the magnitude of the serum creatinine change in these months is a marker of the relationship with long-term survival. For that reason, renal function (serum creatinine) is included as a main efficacy variable.