Pierre Marquet1, Laetitia Albano2, Jean-Baptiste Woillard3, Lionel Rostaing4, Nassim Kamar5, Charlotte Sakarovitch6, Philippe Gatault7, Matthias Buchler7, Bernard Charpentier8, Eric Thervet9, Elisabeth Cassuto2. 1. Univ. Limoges, UMR_S 850, Limoges, France; INSERM, U850, Limoges, France; CHU Limoges, Service de pharmacologie, toxicologie et pharmacovigilance, Limoges, France; FHU SUPPORT, Limoges, France. Electronic address: pierre.marquet@unilim.fr. 2. Transplant Unit, University Hospital, Nice, France. 3. Univ. Limoges, UMR_S 850, Limoges, France; INSERM, U850, Limoges, France; CHU Limoges, Service de pharmacologie, toxicologie et pharmacovigilance, Limoges, France; FHU SUPPORT, Limoges, France. 4. INSERM U563, IFR-BMT, CHU Purpan, Toulouse, France; Department of Nephrology and Organ Transplantation, CHU Rangueil, Toulouse, France; Université Toulouse III Paul Sabatier, Toulouse, France. 5. Department of Nephrology and Organ Transplantation, CHU Rangueil, Toulouse, France; Université Toulouse III Paul Sabatier, Toulouse, France; INSERM U1043, IFR-BMT, CHU Purpan, Toulouse, France. 6. Department of Clinical research and Innovation, Nice University Hospital, Nice, France. 7. Department of Nephrology and Clinical Immunology, Bretonneau Hospital, CHRU de Tours, EA4245, Université François-Rabelais de Tours, Tours, France. 8. Department of Nephrology, University Hospital of Bicêtre, Kremlin Bicêtre, IFNRT, UMR 1197 INSERM-Université Paris-Sud, Villejuif, France. 9. Nephrology Department, Hopital Europeen Georges Pompidou, APHP, Paris, France; Université Paris Descartes, Paris France; Unite INSERM UMRS 1147, France.
Abstract
BACKGROUND: Several studies found differences in tacrolimus whole blood trough levels (C0) or area-under-the curve (AUC) between the twice-daily (Tac-BID) and once-daily (Tac-OD) formulations given to kidney transplant recipients at equal doses. As C0 is widely used as a surrogate of the AUC for individual dose adjustment, this study investigated the correlation and proportionality between C0 and the 24h-AUC, depending on the formulation, time post-transplantation, pharmacogenetics traits and other individual characteristics. METHODS:45 adult kidney transplant recipients were randomized to receive either Tac OD or Tac BID. On days 8±1 (D8) and 90±3 (month 3, M3), blood samples were collected over 24h in both groups. Tacrolimus concentrations were determined using HPLC-MS/MS and common CYP3A5, CYP3A4 and ABCB1 genotypes characterized using allelic discrimination assays. Tacrolimus population pharmacokinetics was studied in the two patient groups using the Iterative Two Stage (ITS) technique, considering a one-compartment model with two gamma laws to describe the absorption phase. Bayesian estimation based on the C0, C1h and C3h concentrations was employed to estimate individual Tac AUC0-12h and AUC12-24h (for Tac BID), or AUC0-24h (for Tac OD). Multiple linear regression was used to evaluate the influence of Tac formulation, post-transplantation period, recipient gender, existing glucose metabolism disorders, and CYP3A5, CYP3A4 and ABCB1 genotypes on C0, AUC0-24h and the AUC-to-trough concentration ratios. RESULTS: The Full Analysis Set comprised 22 patients on Tac OD and 20 on Tac BID. Tac exposure indices as well as their time evolution were similar in the two groups. Multi-linear modeling analysis showed that the Tac dose was higher with Tac-OD than Tac-BID, on D8 than at M3 and in CYP3A5 expressors (p<0.0001 for all). No such influence was found on C0 or C24h, while the AUC0-24h was significantly higher on D8 than at M3. The AUC0-24h/C0 ratio was not affected by the drug formulation and the polymorphisms studied, but it was significantly lower on D8 than at M3 (p=7.8×10-5). In contrast, both the post-transplantation period (p=1.53×10-4), and CYP3A5 expression (p=0.003) had a significant influence on the AUC0-24h/C24h ratio, explaining 19% and 12% of its variability, respectively. Consistently, for both Tac formulations, the AUC0-24h was better correlated with C24h than C0, and for Tac-BID the AUC0-12h was better correlated with C12h than C0. CONCLUSIONS: This study confirms that the precisely timed 12h- or 24h-post-dose blood concentration (as opposed to the vaguely defined 'trough level') is a convenient surrogate of the 24h-AUC of tacrolimus for the two TAC formulations over the first 3 months post-transplantation. Still, for a given C24h value, AUC0-24h was higher on D8 and in CYP3A5 expressors. Bayesian estimation of AUC0-12h for TAC BID and AUC0-24h for TAC OD is feasible using only 3 time points within the first 3h, thus giving access to the actual overall exposure.
RCT Entities:
BACKGROUND: Several studies found differences in tacrolimus whole blood trough levels (C0) or area-under-the curve (AUC) between the twice-daily (Tac-BID) and once-daily (Tac-OD) formulations given to kidney transplant recipients at equal doses. As C0 is widely used as a surrogate of the AUC for individual dose adjustment, this study investigated the correlation and proportionality between C0 and the 24h-AUC, depending on the formulation, time post-transplantation, pharmacogenetics traits and other individual characteristics. METHODS: 45 adult kidney transplant recipients were randomized to receive either Tac OD or Tac BID. On days 8±1 (D8) and 90±3 (month 3, M3), blood samples were collected over 24h in both groups. Tacrolimus concentrations were determined using HPLC-MS/MS and common CYP3A5, CYP3A4 and ABCB1 genotypes characterized using allelic discrimination assays. Tacrolimus population pharmacokinetics was studied in the two patient groups using the Iterative Two Stage (ITS) technique, considering a one-compartment model with two gamma laws to describe the absorption phase. Bayesian estimation based on the C0, C1h and C3h concentrations was employed to estimate individual Tac AUC0-12h and AUC12-24h (for Tac BID), or AUC0-24h (for Tac OD). Multiple linear regression was used to evaluate the influence of Tac formulation, post-transplantation period, recipient gender, existing glucose metabolism disorders, and CYP3A5, CYP3A4 and ABCB1 genotypes on C0, AUC0-24h and the AUC-to-trough concentration ratios. RESULTS: The Full Analysis Set comprised 22 patients on Tac OD and 20 on Tac BID. Tac exposure indices as well as their time evolution were similar in the two groups. Multi-linear modeling analysis showed that the Tac dose was higher with Tac-OD than Tac-BID, on D8 than at M3 and in CYP3A5 expressors (p<0.0001 for all). No such influence was found on C0 or C24h, while the AUC0-24h was significantly higher on D8 than at M3. The AUC0-24h/C0 ratio was not affected by the drug formulation and the polymorphisms studied, but it was significantly lower on D8 than at M3 (p=7.8×10-5). In contrast, both the post-transplantation period (p=1.53×10-4), and CYP3A5 expression (p=0.003) had a significant influence on the AUC0-24h/C24h ratio, explaining 19% and 12% of its variability, respectively. Consistently, for both Tac formulations, the AUC0-24h was better correlated with C24h than C0, and for Tac-BID the AUC0-12h was better correlated with C12h than C0. CONCLUSIONS: This study confirms that the precisely timed 12h- or 24h-post-dose blood concentration (as opposed to the vaguely defined 'trough level') is a convenient surrogate of the 24h-AUC of tacrolimus for the two TAC formulations over the first 3 months post-transplantation. Still, for a given C24h value, AUC0-24h was higher on D8 and in CYP3A5 expressors. Bayesian estimation of AUC0-12h for TAC BID and AUC0-24h for TAC OD is feasible using only 3 time points within the first 3h, thus giving access to the actual overall exposure.
Authors: Pere Fontova; Helena Colom; Raül Rigo-Bonnin; Lisanne N van Merendonk; Anna Vidal-Alabró; Nuria Montero; Edoardo Melilli; Maria Meneghini; Anna Manonelles; Josep M Cruzado; Juan Torras; Josep Maria Grinyó; Oriol Bestard; Nuria Lloberas Journal: Front Pharmacol Date: 2021-03-17 Impact factor: 5.810