Improvement of Renal Graft Function After Conversion From a Calcineurin Inhibitor Including Immunosuppression to a Mycophenolate Sodium Including Regimen: A 4-year Follow-up

Background. The most common immunosuppressive regimens after renal transplantation include calcineurin inhibitors (CNI). However, due to renal toxicity long-term graft survival does not seem to be positively affected by CNIs. Methods. In the present study, we investigated 17 patients, in which the CM immunosuppression was converted to a CM-free, mycophenolate sodium (MPS) regimen. Conversion was performed due to progressive impairment of the graft function from suspected CM toxicity. We retrospectively analyzed graft function as well as toxicity and surrogate markers for 4 years before and 4 years after conversion using a repeated-measures mixed model data analysis and/or a paired sample t-test. Results. The mean time point of therapy conversion was 11.2 +/- 4.6 years after transplantation. Within 1 month of CNI discontinuation, allograft function improved significantly, remaining at a significant level for 2 years. The estimated glomerular filtration rate increased from 43.4 +/- 14.8 to a maximum of 55.7 +/- 21.7 mL/min at 1 year after conversion (P = .0027). After 4 years, the end of the observation period, renal function was similar to the baseline. There were no significant side effects. Conclusion. These data suggested that, when chronic CM-toxicity is suspected, renal allograft recipients may benefit from CM withdrawal in favor of a MPS-including immunosuppressive regimen.