Effect of Rifampin on the Disposition of Brivaracetam in Human Subjects: Further Insights into Brivaracetam Hydrolysis.

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).

Interaction between brivaracetam (100 mg/day) and a combination oral contraceptive: a randomized, double-blind, placebo-controlled study.

This randomized, double-blind, placebo-controlled, two-way crossover study aimed to assess the pharmacokinetic interactions between brivaracetam 100 mg/day and a combination oral contraceptive (OC) containing 30 µg ethinylestradiol and 150 µg levonorgestrel. The study was performed in 28 healthy women over five 28-day menstrual cycles: baseline (OC only), two treatment cycles with brivaracetam (50 mg b.i.d.) or placebo coadministered with OC separated by a wash-out cycle (OC only), and a follow-up cycle (OC only). The OC was administered on days 1-21 of each cycle, and brivaracetam or placebo on days 1-28 of the treatment cycles. Pharmacokinetics of ethinylestradiol and levonorgestrel were determined on day 20; brivaracetam morning trough levels on days 20 (with OC) and 29 (without OC) were compared. Cmax (maximum plasma concentration) and AUC (area under the plasma concentration versus time curve) ratios for brivaracetam versus placebo (90% confidence interval [CI]) were 0.96 (0.88-1.04) and 0.90 (0.86-0.95) for ethinylestradiol, and 0.95 (0.91-0.99) and 0.92 (0.88-0.97) for levonorgestrel, within predefined bioequivalence limits (0.80-1.25). Brivaracetam trough levels were similar on days 20 and 29 (ratio 1.08; 90% CI 0.98-1.18). No differences in breakthrough bleeding were seen across the five cycles. It was concluded that there were no interactions between brivaracetam 100 mg/day and the OC.

Pharmacological interactions between brivaracetam and ethanol in healthy males.

This double-blind, randomized, three-way crossover study explored the potential pharmacokinetic and pharmacodynamic interactions between ethanol and brivaracetam in 18 healthy males, as required for the development of CNS-active drugs. Subjects received (A) ethanol+brivaracetam, (B) ethanol placebo+brivaracetam and (C) ethanol+brivaracetam placebo. Ethanol was infused as a 5.5-hour intravenous clamp with the first 0.5-hour as loading phase to a target level of 0.6 g/L, and brivaracetam was orally administered as a single 200 mg dose. No relevant pharmacokinetic interactions were observed. Co-administration of brivaracetam and ethanol resulted in decreased saccadic peak velocity, smooth pursuit, adaptive tracking and VAS alertness, and increased body sway, saccadic reaction time and VAS score for ethanol effect compared with brivaracetam alone or ethanol alone. Additionally, the immediate word recall scores were generally lower when brivaracetam was co-administered with ethanol, whereas the delayed word test did not show clear additional effects. A post-hoc exploratory analysis for supra-additivity suggested that most pharmacodynamic effects were likely to be additive in nature, except for adaptive tracking, which appeared to be slightly supra-additive. In conclusion, brivaracetam increased ethanol effects on psychomotor function, attention and memory in healthy males. Intake of brivaracetam with alcohol is not recommended.

The FcRn inhibitor rozanolixizumab reduces human serum IgG concentration: A randomized phase 1 study.

Pathogenic immunoglobulin G (IgG) autoantibodies characterize some human autoimmune diseases; their high concentration and long half-life are dependent on recycling by the neonatal Fc receptor (FcRn). Inhibition of FcRn is an attractive new treatment concept for IgG-mediated autoimmune diseases. Rozanolixizumab (UCB7665; CA170_01519.g57 IgG4P) is an anti-human FcRn monoclonal antibody. In cynomolgus monkeys, rozanolixizumab reduced IgG (maximum 75 to 90% by about day 10), was well tolerated, and did not increase risk of infection. We also report a first-in-human, randomized, double-blind, placebo-controlled, dose-escalating study of intravenous (IV) or subcutaneous (SC) rozanolixizumab in healthy subjects (NCT02220153). The primary objective was to evaluate safety and tolerability. Secondary objectives were assessment of rozanolixizumab pharmacokinetics and pharmacodynamics, including effects on circulating IgG concentrations. Forty-nine subjects were randomized to receive rozanolixizumab (n = 36) or placebo (n = 13) across six cohorts. The first three cohorts received IV doses, and the subsequent three cohorts received SC doses, of rozanolixizumab 1, 4, or 7 mg/kg (n = 6 for each cohort; plus n = 7 or 6 for placebo, respectively). The most frequent treatment-emergent adverse event [TEAE; headache, 14 of 36 (38.9%) subjects] was dose-dependent and more prominent after IV administration. Severe TEAEs occurred in four subjects, all in the highest-dose IV group [headache (n = 3) and back pain (n = 1)]. Rozanolixizumab pharmacokinetics demonstrated nonlinear increases with dose. There were sustained dose-dependent reductions in serum IgG concentrations (IV and SC rozanolixizumab). These data provide clinical evidence for the therapeutic potential of rozanolixizumab.

Effect of brivaracetam on CYP3A activity, measured by oral midazolam.

Brivaracetam is a synaptic vesicle protein 2A ligand in phase III development for epilepsy. A phase I, open-label, randomized study was conducted in 42 healthy male participants to assess the effect of brivaracetam on CYP3A activity using midazolam as a probe. Participants were randomized to oral brivaracetam 5, 50, or 150 mg/day from Day 8 to Day 14. A single oral dose (7.5 mg) of midazolam was administered on Days 1, 13, and 20, and full pharmacokinetic profiles were obtained. For all brivaracetam doses, the areas under the plasma concentration-time curves from 0 to infinity (AUCinf ) for midazolam and 1'-hydroxymidazolam were similar on Days 13 and 20 compared with Day 1. Following brivaracetam 150 mg/day, the Day 13/Day 1 AUCinf ratio (90% confidence interval) was 1.09 (0.97, 1.21) and 1.04 (0.93, 1.17) for midazolam and 1'-hydroxymidazolam, respectively. For the Day 20/Day 1 comparison, the corresponding AUCinf ratios were 1.10 (0.98, 1.23) and 1.07 (0.97, 1.18). Maximum midazolam plasma concentration was increased on both Day 13 and Day 20 vs. Day 1 but the relevance of this finding was unclear. This study indicates that brivaracetam up to 150 mg/day has no significant inducing or inhibiting effect on CYP3A activity.

Pharmacokinetics of the antiepileptic drug levetiracetam in healthy Japanese and Caucasian volunteers following intravenous administration.

The intravenous (iv) formulation of levetiracetam has been available in clinical practice worldwide for several years, but not in Japan. Two open-label studies were conducted: Study A evaluated the bioequivalence of iv and oral tablet formulations in healthy Japanese volunteers; and Study B subsequently compared the pharmacokinetics of iv levetiracetam in healthy Japanese and Caucasian volunteers. Study A had a randomised, two-way crossover design; a single 1,500 mg levetiracetam dose was administered as a 15-min iv infusion and as 3 × 500 mg oral tablets to Japanese volunteers. In Study B, 1,500 mg levetiracetam was administered as single and repeated 15-min iv infusions to Japanese and Caucasian volunteers. Overall, 26/27 volunteers completed Study A and 32/32 (16 Japanese; 16 Caucasian) completed Study B. In Study A, the point estimate and 90 % confidence interval (CI) for the geometric least squares mean (LSM) ratio (iv vs oral) were fully included within the acceptance range for bioequivalence (0.85-1.25) for the area under plasma concentration-time curve from 0 to last quantifiable observation (AUClast 0.97 [0.95, 0.99]), but not for the maximum plasma concentration (C max 1.64 [1.47, 1.83]). In Study B, after a single iv infusion, the point estimates (90 % CI) for the geometric LSM ratio (Japanese vs Caucasian) for body weight-normalised C max and AUClast were 1.21 (1.07, 1.36) and 0.97 (0.90, 1.04), respectively. Corresponding values after repeated iv infusions were C max,ss 1.01 (0.91, 1.12) and AUCτ,ss 0.89 (0.83, 0.96). Levetiracetam was well tolerated in both studies. Study A did not demonstrate the bioequivalence of single doses of levetiracetam 1,500 mg administered as an iv infusion and as oral tablets in healthy Japanese adults. Study B, however, showed that pharmacokinetic profiles were generally similar between Japanese and Caucasian adults after single and repeated iv infusions of levetiracetam 1,500 mg.

Modulation of cell cycle for enhancement of antibody productivity in perfusion culture of NS0 cells.

A prolonged period of high productivity at high cell density is desirable for industrial production of biopharmaceuticals. Previous efforts have shown that cessation of cell proliferation in low cell density culture results in increased productivity. We report here further results on multigenic manipulation of cell cycle and apoptosis to enhance productivity at high cell density. The NS0 6A1/4-9F myeloma cell line, which constitutively expresses a chimeric IgG4 antibody and inducibly expresses the p21(CIP1) cyclin-dependent kinase inhibitor has been further engineered to constitutively overexpress the Y28 mutant Bcl-2 anti-apoptotic protein. The effects of overexpression of p21(CIP1) and Bcl-2 on cell proliferation, cell viability, and antibody production has been investigated in batch and continuous perfusion cultures. In both cultures the p21(CIP1) protein arrested cell proliferation, confirming the previous results in low-density culture of 4-fold increase in antibody production, whereas mutant Bcl-2 expression has not resulted in any significant improvement in cell viability of arrested cells. This study demonstrates that it is possible to enhance the productivity of relatively high-density continuous mammalian cell cultures by arresting the cell cycle in G1 phase.

Brivaracetam single and multiple rising oral dose study in healthy Japanese participants: influence of CYP2C19 genotype.

Brivaracetam is a high-affinity synaptic vesicle protein 2A ligand, in phase 3 clinical development for epilepsy. A phase 1, single-center, randomized, double-blind, placebo-controlled, single (2.5-100 mg) and multiple (2.5-50 mg twice daily) rising oral dose study (N01209) was conducted to assess the adverse event profile and pharmacokinetics of brivaracetam in healthy Japanese men, and the influence of the cytochrome P450 (CYP) 2C19 genotype. Plasma and urine were collected serially for analysis of brivaracetam and its three main metabolites: acid, hydroxy and hydroxy acid. Overall, 79/80 randomized participants completed the study. Brivaracetam was generally well tolerated. After single- and multiple-dose administration, brivaracetam was rapidly absorbed, with dose-proportional pharmacokinetics over the dose ranges tested. Steady state was reached after 2 days of repeated dosing. Brivaracetam clearance (averaged across the five single dose levels) was reduced from 0.99 mL/min/kg in homozygous extensive metabolizers (EM; n = 10) to 0.81 mL/min/kg (-18%) in heterozygous EM (n = 17) and 0.70 mL/min/kg (-29%) in poor metabolizers (PM; n = 9). Exposure and urinary excretion of hydroxy metabolite were reduced 10-fold in PM participants, compared with EM participants. Results suggest that brivaracetam is hydroxylated by CYP2C19, but this pathway is minor compared with hydrolysis to the acid metabolite.

Regulation of cell cycle and productivity in NS0 cells by the over-expression of p21CIP1.

We have constructed NS0 myeloma cell lines that inducibly express the p21CIP1 cyclin dependent kinase inhibitor, using the Lacswitch system. Ectopic p21(CIP1) protein expression was rapidly induced within 12 h of addition of IPTG, causing G1-phase arrest and almost complete inhibition of cell proliferation. The production of a chimeric IgG4 antibody, expressed constitutively from an independent promoter, was found to be significantly increased by more than 4-fold in p21CIP1-arrested cells. This study demonstrates for the first time the successful construction of anchorage-independent and proliferation-controlled NS0 cell lines with enhanced secreted chimeric antibody production independent of the inducible promoter activity used to achieve cytostasis.