Mycophenolate Mofetil Initiation in Renal Transplant Patients at Different Times Posttransplantation: The TranCept Switch Study

Background. Despite evidence of favorable long-term effects of mycophenolate mofetil (MMF) in renal transplantation, its introduction at different times posttransplant has not been studied in large cohorts. Methods. Single-organ renal allograft recipients (n=2217) who had MMF introduced 6 months to more than 20 years posttransplantation for various reasons were included in TranCept Switch, a multicenter, noninterventional, observational 4-year study. Changes in renal function before and after the introduction of MMF were analyzed. Results. MMF was introduced because of renal function decline in 43% of patients and poor tolerability with previous treatment in 23% of patients. The change in slope of the calculated glomerular filtration rate (modification of diet in renal diseases formula) regression line before and after MMF initiation was +2.01 mL/min per year (P<0.001) on average. The greatest benefit was noted in patients who received MMF because of renal function decline and in whom calcineurin inhibitor treatment was subsequently reduced or withdrawn (+3.09 mL/min per year). Time from transplantation to MMF introduction influenced the glomerular filtration rate at MMF initiation (slow progressive deterioration) but not the direction of the slope change, which was positive even for late introduction. Conclusion. MMF introduction may be associated with improvement or stabilization of renal function even several years after transplantation.