Aim: Once daily extended-release tacrolimus (tac-ER) was introduced to support medication adherence in kidney transplant (KTx) recipients, with similar efficacy to immediate-release tacrolimus (tac-IR). However, most of the experiences regarding tac-ER efficacy were obtained from the switches from tac-IR to tac-ER in kidney transplant recipients (KTRs). In this study, we aimed to demonstrate 1-year outcomes of de novo use of tac-ER in KTRs.
 Material and Method: This single-center retrospective study included 72 de novo KTRs between January 2020 and January 2021. KTRS were divided into two groups who received a tac-ER or tac-IR. 1-year allograft functions, allograft survival, daily doses of tacrolimus in milligram/day and milligram/kg/day, trough levels, and acute rejection episodes were compared between the two groups. The factors that might have an impact on allograft functions and acute rejection episodes also were investigated.
 Results: A total of 69 de novo kidney allograft recipients (30 recipients in the tac-ER and 39 recipients in the tac-ER groups); were evaluated. Three KTRs were excluded due to the deaths within the early posttransplant period. Serum creatinine and tacrolimus trough levels were similar for 12 months after transplantation (p>0.05). More daily tacrolimus doses (in milligram/day and milligram/kg/day) were required to obtain a targeted trough level up to 3 months in the tac-ER group. Acute rejection rates also were found similar between the two groups (p=0.281). Univariate regression analysis demonstrated that higher total daily tacrolimus doses within a posttransplant month 1 may (milligram/kg/day) have an impact on lower acute rejection episode(s) independent of tacrolimus trough levels (p=0.02).
 Conclusion: De novo use of extended-release tacrolimus Advagraf® is as effective as immediate-release tacrolimus in preventing acute rejection episode(s) and provides satisfactory 1-year allograft function and survival.