title: Effect of Rifampin on the Disposition of Brivaracetam in Human Subjects: Further Insights into Brivaracetam Hydrolysis.
abstract: Brivaracetam (BRV) is a high-affinity synaptic vesicle protein 2A ligand developed for the treatment of uncontrolled partial-onset seizures. The present phase I, open-label, two-way crossover study was designed to assess the effect of rifampin on the pharmacokinetics of BRV and its hydroxy (BRV-OH), acid (BRV-AC), and hydroxy acid (BRV-OHAC) metabolites. Twenty-six healthy subjects received BRV (150-mg single oral dose) either alone or following 5 days of rifampin 600 mg/day. BRV and its metabolites were examined for their plasma profiles and urinary excretion. Pharmacokinetic modeling was developed to estimate the rate constants of the various metabolic routes. Parallel in vitro assays were conducted to characterize the hydrolysis of BRV to BRV-AC as well as to identify any potential effect of rifampin on the hydrolysis reaction. Rifampin did not significantly affect the maximum plasma concentration (Cmax) of BRV, but decreased its area under the curve (AUC) by 45%. In addition, rifampin significantly increased the AUC of BRV-OH (+109%), decreased the AUC of BRV-AC (-53%), but had little effect on BRV-OHAC (-10%). In vitro assays showed that the major urinary metabolite BRV-AC (33% of the dose) was likely to be formed by amidase EC 3.5.1.4. In vitro data indicated that the enzyme was not significantly inhibited nor induced by rifampin. Modeling confirmed that all of the observed changes in vivo were secondary to the induction of the CYP2C19-mediated hydroxylation of BRV to BRV-OH (3.7-fold increase in the rate constant).
authors.affiliation: UCB Pharma, Braine-l'Alleud, Belgium (A.S., S.W., D.T., B.G., M.R., H.C., J.-M.N.); and Clinical Pharmacology Unit, University Hospital Center, Liège, Belgium (A.J.S.) Armel.Stockis@ucb.com.
authors.forename: Armel
authors.initials: A
authors.lastname: Stockis
authors.affiliation: UCB Pharma, Braine-l'Alleud, Belgium (A.S., S.W., D.T., B.G., M.R., H.C., J.-M.N.); and Clinical Pharmacology Unit, University Hospital Center, Liège, Belgium (A.J.S.).
authors.forename: Shikiko
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: UCB Pharma, Braine-l'Alleud, Belgium (A.S., S.W., D.T., B.G., M.R., H.C., J.-M.N.); and Clinical Pharmacology Unit, University Hospital Center, Liège, Belgium (A.J.S.).
authors.forename: André J
authors.initials: AJ
authors.lastname: Scheen
authors.affiliation: UCB Pharma, Braine-l'Alleud, Belgium (A.S., S.W., D.T., B.G., M.R., H.C., J.-M.N.); and Clinical Pharmacology Unit, University Hospital Center, Liège, Belgium (A.J.S.).
authors.forename: Dominique
authors.initials: D
authors.lastname: Tytgat
authors.affiliation: UCB Pharma, Braine-l'Alleud, Belgium (A.S., S.W., D.T., B.G., M.R., H.C., J.-M.N.); and Clinical Pharmacology Unit, University Hospital Center, Liège, Belgium (A.J.S.).
authors.forename: Brigitte
authors.initials: B
authors.lastname: Gerin
authors.affiliation: UCB Pharma, Braine-l'Alleud, Belgium (A.S., S.W., D.T., B.G., M.R., H.C., J.-M.N.); and Clinical Pharmacology Unit, University Hospital Center, Liège, Belgium (A.J.S.).
authors.forename: Maria
authors.initials: M
authors.lastname: Rosa
authors.affiliation: UCB Pharma, Braine-l'Alleud, Belgium (A.S., S.W., D.T., B.G., M.R., H.C., J.-M.N.); and Clinical Pharmacology Unit, University Hospital Center, Liège, Belgium (A.J.S.).
authors.forename: Hugues
authors.initials: H
authors.lastname: Chanteux
authors.affiliation: UCB Pharma, Braine-l'Alleud, Belgium (A.S., S.W., D.T., B.G., M.R., H.C., J.-M.N.); and Clinical Pharmacology Unit, University Hospital Center, Liège, Belgium (A.J.S.).
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Nicolas
mesh_terms: D000293:Adolescent; D000328:Adult; D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D000927:Anticonvulsants / Q000493:pharmacokinetics*; D019540:Area Under Curve; D018592:Cross-Over Studies; D065731:Cytochrome P-450 CYP2C19 / Q000378:metabolism; D064368:Healthy Volunteers; D006801:Humans; D006868:Hydrolysis / Q000187:drug effects*; D006880:Hydroxy Acids / Q000378:metabolism; D006900:Hydroxylation / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D011760:Pyrrolidinones / Q000493:pharmacokinetics*; D012293:Rifampin / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D000904:Antibiotics, Antitubercular; D000927:Anticonvulsants; D006880:Hydroxy Acids; D011760:Pyrrolidinones; D065731:Cytochrome P-450 CYP2C19; C482793:brivaracetam; D012293:Rifampin