Intra-patient variability in tacrolimus exposure is not reduced by conversion from twice-daily to a once-daily tacrolimus formulation.
N. Shuker, T. van Gelder, M. Cadogan, W. Weimar, D.A. Hesselink
Moderator(s): S.A. Nurmohamed en M. Seelen
Location(s): Grote zaal
Category:
Background: The widely used immediate-release tacrolimus formulation (Prograf®; Tac-TD) is given twice daily and is the standard strategy for patients on tacrolimus. A prolonged-release oral dosage form of tacrolimus (Advagraf®; Tac-OD) has been developed to improve adherence in transplant recipients by allowing a once-daily dosing alternative. However, the clinical use of tacrolimus is complicated by considerable intra-patient variability (IPV) in tacrolimus exposure, which is defined by fluctuating drug concentrations within a certain period during which drug dosage remains unchanged. As a high IPV in tacrolimus exposure is a possible risk factor for rejection and graft failure, improved adherence to Tac-OD might reduce IPV in tacrolimus exposure. The main purpose of this study was to investigate whether conversion from Tac-TD to Tac-OD reduces IPV in tacrolimus exposure.
Methods: We converted 252 stable renal transplant recipients from Tac-TD to Tac-OD on a 1mg:1mg total daily dose basis. After conversion, patients were followed up for 12 months for tacrolimus predose blood concentrations (C0), serum creatinine, estimated glomerular filtration rate (eGFR), and proteinuria. These parameters were compared with those collected at all outpatient visits in the period 12±3-months before conversion (Prograf® period).
Results: For analysis, we included patients for whom 3 or more C0 values were available (n=220). After conversion to Tac-OD, mean C0 was significantly lower, falling from 6.10 ± 1.76 µg/L to 5.37 ± 1.29 µg/L, corresponding to a 12% reduction (P<0.001). Both drugs had similar IPV (Tac-TD: 18.88 ± 9.16% versus Tac-OD: 18.85 ± 9.97%; P=0.976). Renal function remained stable (eGFR before conversion: 47.31 ± 15.47 ml/min versus eGFR 12 months after conversion: 47.54 ± 15.50 ml/min; P=0.656).
Conclusions: Although conversion from Tac-TD to Tac-OD significantly reduces tacrolimus exposure as measured by C0, it does not reduce IPV in tacrolimus exposure. This study provides evidence that conversion from Tac-TD to Tac-OD is safe.