Pharmacokinetic Analysis of Mycophenolate Mofetil and Enteric-Coated Mycophenolate Sodium in Calcineurin Inhibitor-Free Renal Transplant Recipients.

BACKGROUND: Considerable interest exists in identifying calcineurin inhibitor (CNI)-free and thus, less-toxic immunosuppressive regimens, with mycophenolic acid (MPA)-based treatments being a suitable approach. Because pharmacokinetic analyses of MPA treatments in stable CNI-free renal transplant recipients are lacking, the authors aimed at comparing the steady-state pharmacokinetic characteristics of MPA in patients on stable treatment with mycophenolate mofetil (MMF) or enteric-coated mycophenolate sodium (EC-MPS) plus prednisone (≤5 mg/d). METHODS: In the prospective, nonrandomized, open-label study, patients with stable transplant function since ≥6 months received their routine single dose of either MMF (n = 12) or EC-MPS (n = 11). The MPA plasma concentration was recorded over 12 hours. Parameters assessed were predose MPA concentration (C0), postdose minimum and maximum concentration (Cmin and Cmax), time to maximum concentration (Tmax), and area under the concentration-time curve (AUC) for the 12-hours of exposure (AUC0-12). RESULTS: Baseline characteristics were comparable between both the groups. Consistent with enteric coating, the mean Tmax was significantly longer after the intake of EC-MPS compared with MMF (2.2 versus 0.8 hours; P = 0.0002). The exposure measures Cmin, Cmax, and AUC0-12 were not significantly different despite the higher mean MPA equivalent dose in patients receiving MMF compared with those receiving EC-MPS (85% versus 64% of the recommended single dose, respectively). Exposures as reflected by the median AUC0-12 values were 50.7 and 58.7 mg·h·L with MMF and EC-MPS, respectively (P = 0.340). All patients achieved a target AUC of >30 mg·h·L, and 61% had an AUC of >50 mg·h·L. CONCLUSIONS: The study provides first results on the steady-state pharmacokinetics of the 2 MPA drugs in CNI-free immunosuppressant regimens. Pharmacokinetic parameters measured in this study under real-life conditions were comparable in patients receiving MMF or EC-MPS.