Everolimus as Primary Immunosuppression in Kidney Transplantation: Experience in Conversion From Calcineurin Inhibitors

Background. We analyzed our clinical experience with everolimus (EVL) and identified prognostic factors for a successful conversion. Methods. Retrospective study of 220 kidney recipients consecutively converted to EVL with calcineurin inhibitor elimination. We studied risk factors for proteinuria at 1 year after conversion, decline in renal function, and graft survival. Results. Baseline creatinine clearance was 52.4 +/- 17.8 mL/min vs. 53.4 +/- 20.1 mL/min 1 year after conversion (P = 0.150). Median proteinuria increased from 304 mg/day (interquartile range 160-507) to 458 mg/day (interquartile range 238-892; P < 0.001). Risk factors for development of proteinuria >= 900 mg/day (P75) at 1-year postconversion were creatinine clearance less than 60 mL/min (odds ratio [OR] 3.37; 95% confidence interval [CI]: 1.15-9.89), serum triglycerides >= 150 mg/day (OR 4.35; 95% CI: 1.70-11.17), no treatment with prednisone (OR 3.04; 95% CI: 1.22-7.59), baseline proteinuria >= 550 mg/day (OR 10.37; 95% CI: 3.99-26.99), and conversion >= 3 years after transplant (OR 5.77; 95% CI: 1.89-17.59). An interaction was observed between baseline proteinuria and time to conversion: in patients with baseline proteinuria >= 550 mg/day, the risk of developing proteinuria >= 900 mg/day was 77.1% if they were converted after >= 3 years posttransplant. However, this risk was 29.8% in the subgroup converted before (P = 0.02). Actuarial graft survival at 1 and 4 years postconversion was 98.2% and 86.5%, respectively. Baseline proteinuria >= 550 mg/day was a risk factor for graft loss in patients converted after the third year but not in patients converted before this time. EVL discontinuation rate was 24% in the first year postconversion. Conclusions. Conversion to EVL and elimination of calcineurin inhibitors is safe. Success depends on not making late conversions and not converting patients with high baseline proteinuria.