Efficacy and Safety of Early Cyclosporine Conversion to Sirolimus with Continued MMF—Four‐Year Results of the Postconcept Study

Calcineurin inhibitor (CNI) withdrawal has been used as a strategy to improve renal allograft function. We previously reported that conversion from cyclosporine A (CsA) to sirolimus (SRL) 3 months after transplantation significantly improved renal function at 1 year. In the Postconcept trial, 77 patients in the SRL group and 85 in the CsA group were followed for 48 months. Renal function (Cockcroft and Gault) was significantly better at month 48 (M48) in the SRL group both in the intent‐to‐treat population (ITT): 62.6 mL/min/1.73 m2 versus 57.1 mL/min/1.73 m2 (p = 0.013) and in the on‐treatment population (OT): 67.5 mL/min/1.73 m2 versus 57.4 mL/min/1.73 m2 (p = 0.002). Two biopsy proven acute rejection episodes occurred after M12 in each group. Graft and patient survival were comparable (graft survival: 97.4 vs. 100%; patient survival: 97.4 vs. 97.6%, respectively). The incidence of new‐onset diabetes was numerically increased in the SRL group (7 vs. 2). In OT, three cancers occurred in the SRL group versus nine in the CsA group and mean proteinuria was increased in the SRL group (0.42 ± 0.44 vs. 0.26 ± 0.37; p = 0.018). In summary, the renal benefits associated with conversion of CsA to SRL, at 3 months posttransplantation, in combination with MMF were maintained for 4 years posttransplantation. A randomized study of an early cyclosporine to sirolimus conversion at 3 months after transplantation (the CONCEPT study) shows that the renal benefit observed at 1 year is maintained and even more pronounced at 4 years.