Background: One of the most important causes of graft loss is chronic nephrotoxicity from calcineurin inhibitors. The aim of this study was to evaluate the feasibility and to assess the impact on rejection risk, graft loss and renal allograft function of converting patients from tacrolimus (Tac) to sirolimus (SRL) at one yr post-transplantation (Tx) using a prednisone-free immunosuppressive regimen.
Methods: Two hundred fifty-five kidney transplant patients were induced with Alemtuzumab and maintained on a steroid-free regimen with Tac and mycophenolate mofetil. Thirty-seven stable patients (14%) were converted from Tac to SRL at one yr post-Tx.
Results: The two groups were demographically similar. Mean post-tx follow-up was 2.8 +/- 0.2 yr. Patient and graft survival were not statistically different. There was no significant difference in acute rejection episodes between the SRL and Tac groups (21% vs. 15%, p = 0.2). Calculated glomerular filtration rate (GFR), in the SRL group at 2.8 yr post-tx, was 69 +/- 13 mL/min from the one month post-tx GFR of 53 +/- 19 and 59 +/- 23 mL/min from the one month post-tx GFR of 56 +/- 21 mL/min in the Tac group.
Conclusions: Using a prednisone-free regimen, the conversion of Tac to SRL at one yr post-Tx was not associated with an increased risk of acute rejection or graft loss.