Lower Variability of Tacrolimus Trough Concentration After Conversion From Prograf to Advagraf in Stable Kidney Transplant Recipients

Variability of blood trough concentration (C0) in immunosuppressant leads to rejection and graft loss after kidney transplantation.The aim of this study is to prospectively investigate the change of within-patient variability among stable kidney transplant recipients with conversion from twice-daily Prograf to the same milligram-for-milligram daily dose of once-daily Advagraf.The mean age of 129 patients was 51.3±12.1 years. The conversion to Advagraf was administrated at 6.3±4.8 years after transplantation. The daily dose was changed from 4.7±2.0 mg to 4.9±2.1 mg after conversion. Only six patients increased daily dose by 16.7% to 25% to maintain target levels. The whole blood C0 of tacrolimus before conversion was 5.9±1.7 ng/mL. The mean C0 was significantly reduced after conversion to Advagraf; it was 4.9±1.5 ng/mL on the seventh day (P<0.001) and 5.4 to 5.5 ng/mL at 1 to 6 months (P<0.05). Forty-one (31.8%) patients have reduced C0 of more than 25% on the seventh day. The percent coefficient of variation of tacrolimus C0 more than 22.5% before conversion is associated with higher risk of reduced C0 after conversion (P<0.05). Compared with before conversion, less kidney transplant recipients have percent coefficient of variation more than 22.5% after conversion (3.1% vs. 17.4% with P<0.01).The results support that conversion from Prograf to Advagraf among kidney transplant recipient leads to a significantly lower C0 and within-patient variability of tacrolimus C0. The within-patient variability of C0 before conversion influences C0 on the sevent day after conversion to Advagraf.