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

BACKGROUNDS: Variability of blood trough concentration (C0) in immunosuppressant leads to rejection and graft loss after kidney transplantation. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.