NIV Congres

Introduction Therapeutic drug monitoring for tacrolimus (Tac) is universally applied. However, the concentration-effect relationship for Tac is poorly defined. This study investigated whether Tac concentrations are associated with acute rejection in kidney transplant recipients.

Methods Data from three large clinical trials in kidney transplantation (the Symphony-Elite, Opticept, and FDCC trials) were pooled. We used univariate and multivariate analysis to investigate the relationship between BPAR and Tac predose concentration at 5 time points (day 3, 10, and 14, and month 1 and 6 after transplantation).

Results 1304 kidney transplant recipients were included. A total of 136 patients experienced biopsy-proven acute rejection (BPAR), giving an overall incidence of 10.4%. The majority of BPAR occurred within the first month after transplantation (7%). We did not find any significant correlations between Tac predose concentrations and the incidence of BPAR at the different time points. In the multivariate analysis, only delayed graft function (DGF) and the use of induction therapy were independently correlated with BPAR, with an odds ratio of 2.7 [95% CI: 1.8 - 4.0; p < 0.001] for DGF and 0.66 [95% CI: 0.44 - 0.99; p = 0.049] for induction therapy. The other variables, including the Tac predose concentrations, were not statistically significantly associated with BPAR.

Conclusion: We did not find an association between the Tac predose concentrations measured at 5 time points after kidney transplantation and the incidence of acute rejection occurring thereafter. Based on the results of this study it is not possible to define the optimal target concentrations for Tac.