Background
The long-term outcome of kidney transplant recipients on monotherapy with calcineurin inhibitors has been poorly analyzed. This study aimed to describe the long-term outcome of patients on Tac monotherapy (mTac) and to compare this regimen to a standard dual therapy with Tac/MMF.
Material and Methods
This retrospective study included 84 consecutive first kidney recipients transplanted between 1998 and 2003 and followed until 2010. Patients were treated with mTac after the 6th month of transplantation. Survival and incidence of adverse events were analyzed and compared to those of patients treated with Tac/MMF as maintenance regimen after the 6th month of transplantation.
Results
Mean follow-up of the mTac cohort was 8.7±2.2 years. Overall patient and graft survival of the mTac cohort was 91.3% and 86.6%, respectively, at year 8 posttransplant. Tac monotherapy was started in 93.3% of patients at month 6 posttransplant and maintained in 50% of the cohort at the end of the follow-up period. Incidence of acute rejection (AR) and chronic allograft nephropathy (CAN) were 11.9% and 16.6%, respectively. Kaplan-Meyer analysis did not show any difference in patient and graft survival between mTac patients and patients under Tac/MMF. At year 6, compared to Tac/MMF patients, mTac patients had a significantly lower incidence of AR after the 6th month posttransplant and no difference in CAN, cancer, NODAT, and cardiovascular events incidence.
Conclusions
This work suggests that long-term maintenance immunosuppression with mTac is safe in low-immunological risk patients and should be considered for use especially in patients with MMF intolerance.

Keywords: Kidney Transplantation, Tacrolimus, long term follow-up, monotherapy