Outcomes With Conversion From Calcineurin Inhibitors to Sirolimus After Renal Transplantation in the Context of Steroid Withdrawal or Steroid Continuation

Background. A number of studies have suggested that conversion from calcineurin inhibitors (CNI) to sirolimus (SRL) can improve graft function in renal transplant patients. None of these studies has converted patients to SRL in the absence of steroids. Methods. We describe our experience with 278 renal transplants of which 153 were converted from CNI to SRL. The majority of patients had steroids withdrawn after 6 days. Almost all patients received antithymocyte globulin induction and were maintained on mycophenolate mofetil. Results. Six months after conversion, patients remaining on SRL therapy had a mean increase in estimated glomerular filtration rate of 6.93 mL/min/1.73 m(2) (p<0.0001) compared with preconversion values. SRL-converted patients analyzed by intention-to-treat increased estimated glomerular filtration rate by 5.00 mL/min/1.73 m(2) (P=0.0005). Eighty-one percent of patients remaining on SRL had a successful conversion, defined as stable or improved renal function at 6 months. The only factor predictive of unsuccessful conversion was urine protein-to-creatinine ratio more than 1. The benefits of SRL conversion were seen in patients at high immunological risk as well as those at lower risk. Proteinuria increased by a mean of 0.1 (P=0.43) at 6 months. Thirty-six percent of SRL-converted patients experienced adverse effects requiring conversion back to CNI. Rates of rejection, graft loss, and patient death with SRL conversion were low. Conclusions. The results from our clinical practice suggest that even in the absence of steroids, SRL conversion significantly improves renal function, with acceptable rates of adverse events.