Long-term outcomes of tacrolimus conversion to sirolimus in kidney transplant recipients: an eight-year follow-up.

Objective: Calcineurin inhibitors, such as tacrolimus, are associated with long-term nephrotoxicity and renal allograft dysfunction despite evidence of improved kidney transplantation outcomes. Consequently, minimizing calcineurin inhibitor exposure has attracted considerable interest. This study aimed to investigate the long-term outcomes of late conversion of tacrolimus to sirolimus in a steroid-free immunosuppressive regimen in kidney transplant recipients. Methods: We conducted an 8-year retrospective analysis of outcomes in 207 kidney transplant recipients enrolled in a previous randomized clinical trial, in which patients receiving maintenance therapy with tacrolimus and mycophenolate were randomized 2:1 at 6-12 months post-transplantation to conversion from tacrolimus to sirolimus or continuation of tacrolimus. Results: Over the 8-year post-transplant follow-up, the sirolimus cohort exhibited a superior and more preserved GFR compared to the tacrolimus cohort, with a total GFR change of -1.18 mL/min/1.73 m² (95% CI, -4.86 to 3.06) with sirolimus versus -9.57 mL/min/1.73 m² (95% CI, -16.92 to -7.26) with tacrolimus, with a between-group difference of -8.39 mL/min/1.73 m². The two groups did not significantly differ in terms of graft loss, patient survival, or Conclusions: Delayed conversion from tacrolimus to sirolimus (≥6 months post-transplantation) was associated with long-term preserved estimated glomerular filtration rate without a significantly increased risk of renal allograft rejection or graft loss.