Impact of early conversion from tacrolimus to sirolimus on chronic allograft changes in kidney recipients on rapid steroid withdrawal.

BACKGROUND: Calcineurin-inhibitor therapy is a contributing factor to the origin of interstitial fibrosis and tubular atrophy (IFTA). METHODS: We conducted a prospective randomized trial of conversion of tacrolimus to sirolimus at 1-month posttransplant in kidney transplant recipients on rapid steroid withdrawal. We compared the chronic changes (IFTA and sum of Banff chronic scores--Total Score) on protocol biopsies at 1 month, 1 year, and 2 years in all randomized patients. We compared the outcomes between treatment groups and analyzed the impact of previous rejection on the chronic changes. RESULTS: We randomized 122 patients, 62 to sirolimus and 60 to tacrolimus. The 1-year biopsy was performed in 54 patients (90%) of the tacrolimus group and 56 patients (90%) of the sirolimus group. The proportion of biopsies with IFTA more than or equal to 2 and the Total Score more than 2 increased over the 2 years but were not different between the study groups at any time point. On the 1-year biopsy, there was more IFTA, and the fraction with Total Score more than 2 was higher in the tacrolimus group with previous rejection. In the cohort without rejection, there was a significant progression of the IFTA and Total Score between 1 and 2 years in both the sirolimus and tacrolimus groups. CONCLUSION: Conversion from tacrolimus to sirolimus at 1-month posttransplant in kidney transplant recipients on rapid steroid withdrawal does not decrease the progression of chronic changes on protocol biopsies during the first 2 years even in those patients without previous acute rejection.

Results of a prospective randomized trial of sirolimus conversion in kidney transplant recipients on early corticosteroid withdrawal.

BACKGROUND: The use of calcineurin inhibitors is associated with chronic nephrotoxicity and lower glomerular filtration rate (GFR). As a result, one strategy of transplant immunosuppression is calcineurin inhibitor elimination. METHODS: The aim of this study was to determine the outcome of a prospective randomized trial of kidney transplant recipients receiving rapid corticosteroid withdrawal, tacrolimus and mycophenolate mofetil (MMF) for 1 month followed by randomization to switch to sirolimus-MMF or to stay on tacrolimus-MMF. The primary outcome was the difference in measured GFR at 1 year using intention-to-treat analysis. RESULTS: Sixty patients were randomized to stay on tacrolimus-MMF and 62 to sirolimus-MMF. Actual graft survival (including death) at 2 years was 98.4% in the sirolimus group, 96.7% in the tacrolimus group. Sixty-three percentage of the patients in the sirolimus group withdrew during the 2-year period of the study compared with 18% of the tacrolimus group (P<0.0001), primarily related to rejection or medication side effects. Rejection during the first year occurred in 5% of the tacrolimus group and 13% of the sirolimus group (P=0.15). Measured GFR at 1 year (mean±SD) was 57.4±20.7 mL/min/1.73 m in the sirolimus group and 62.7±26.5 mL/min/1.73 m in the tacrolimus group (95% CI of difference -3.7-14.4). CONCLUSIONS: We conclude that conversion from tacrolimus-MMF to sirolimus-MMF at 1 month posttransplant in kidney recipients on rapid steroid withdrawal is poorly tolerated and does not improve GFR at 1 year.