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1.
A Phase 1 Open-Label, Fixed-Sequence Pharmacokinetic Drug Interaction Trial to Investigate the Effect of Cannabidiol on the CYP1A2 Probe Caffeine in Healthy Subjects.
Thai, C, Tayo, B, Critchley, D
Clinical pharmacology in drug development. 2021;(11):1279-1289
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Abstract
This pharmacokinetic (PK) drug-interaction trial investigated the effects of repeated dosing of a plant-derived pharmaceutical formulation of highly purified cannabidiol (CBD; Epidiolex in the United States and Epidyolex in Europe; 100 mg/mL oral solution) on caffeine clearance via modulation of cytochrome P450 (CYP) 1A2 activity in healthy adults. In this phase 1 open-label, fixed-sequence trial, all subjects received a single 200 mg caffeine dose and placebo on day 1. Subjects then titrated CBD from 250 mg once daily to 750 mg twice daily between days 3 and 11 and took 750 mg CBD twice daily between days 12 and 27. On day 26, subjects received a single 200-mg caffeine dose with their morning CBD dose. Plasma concentrations of caffeine and its CYP1A2-mediated metabolite, paraxanthine, were determined on days 1 and 26 and PK parameters derived using noncompartmental analysis. Safety was monitored throughout. Sixteen subjects enrolled, and 9 completed treatment. When caffeine was administered with steady-state CBD, caffeine exposure increased by 15% for Cmax and 95% for AUC0-∞ , tmax increased from 1.5 to 3.0 hours, and t1/2 increased from 5.4 to 10.9 hours compared with caffeine administered with placebo. Under the same conditions, paraxanthine exposure decreased by 22% for Cmax and increased by 18% for AUC0-∞ , tmax increased from 8.0 to 14.0 hours, and t1/2 increased from 7.2 to 13.7 hours. Overall, there were no unexpected adverse events; diarrhea was most common, and 6 subjects discontinued because of elevated liver transaminases. These data suggest that CBD is an inhibitor of CYP1A2.
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An investigation on the effects of carbamazepine and sodium valproate on neuromuscular transmission.
Ay, H, Ethemoğlu, Ö
Acta neurologica Belgica. 2020;(3):545-548
Abstract
The aim of this study was to investigate the effects of sodium valproate (SV) and carbamazepine (CBZ) on neuromuscular transmission using single-fibre electromyography (SFEMG) in patients with epilepsy. We performed SFEMG during the voluntary contraction of extensor digitorum communis muscle. 30 epileptic patients taking SV, 25 epileptic patients taking CBZ, and 25 age-matched healthy volunteers were included in the study. Mean jitter values (MCD) of subjects taking SV and CBZ were compared with normal controls. MCD values of subjects taking SV and CBZ were statistically significantly higher than those of control group. Review of the correlation between disease duration and MCD values of patients showed that MCD values were increased with the prolonged use of drugs, and thus, indicated a positive relationship between these two parameters. These results suggest that both SV and CBZ reduce neuromuscular transmission in patients without a neuromuscular junction disease.
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Response to cannabidiol in epilepsy of infancy with migrating focal seizures associated with KCNT1 mutations: An open-label, prospective, interventional study.
Poisson, K, Wong, M, Lee, C, Cilio, MR
European journal of paediatric neurology : EJPN : official journal of the European Paediatric Neurology Society. 2020;:77-81
Abstract
Epilepsy of Infancy with Migrating Focal Seizures (EIMFS) is a rare, developmental and epileptic encephalopathy most commonly associated with mutations in KCNT1, a potassium channel. Polymorphous migrating focal seizures begin within 6 months of life and are pharmacoresistant to standard anticonvulsants. Additional therapies are needed to decrease seizure frequency and subsequent developmental deterioration associated with EIMFS. Cannabidiol (CBD) has recently arisen in public interest due to its potential in treatment-resistant epilepsies as demonstrated in randomized controlled trials for Dravet Syndrome and Lennox-Gastaut Syndrome. Here we evaluate the response of three patients, all diagnosed with EIMFS secondary to KCNT1 mutations, to pharmaceutical grade CBD. Two patients showed no benefit and have since voluntarily stopped CBD. One patient showed no overall reduction in seizure frequency, however showed a notable reduction in seizure intensity with possible developmental progression. Further studies are needed to assess the potential benefit of CBD in treatment-resistant epilepsies such as EIMFS, with a focus on early identification and intervention.
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The lack of influence of IVS5-91 G>A polymorphism of the SCN1A gene on efficacy of lamotrigine in patients with focal epilepsy.
Markovic, I, Pejanovic-Skobic, N, Bozina, N, Susak Sporis, I, Sporis, D, Basic, S
Neurological research. 2019;(10):930-935
Abstract
Background: IVS5-91G>A (rs3812718) polymorphism of the sodium voltage-gated channel alpha subunit 1 (SCN1A) gene has been associated with inadequate responsiveness to common antiepileptic drugs which act as sodium channel blockers. This study was performed to investigate the effect of IVS5-91G>A (rs3812718) polymorphism on lamotrigine (LTG) efficacy in a cohort of patients with non-lesional focal epilepsy taking LTG as monotherapy. Methods: A total of 100 of patients with non-lesional focal epilepsy on LTG monotherapy was included in this prospective interventional study. After reaching a stable dose of LTG patients were followed-up for 12 consecutive months. LTG responsiveness was defined as a 75% or more reduction in seizure frequency on a stable dose of LTG. Genotyping was performed at the end of the study using standard procedures and data were correlated with clinical data. Results: There were no significant differences in the prevalence of responsiveness to LTG between carriers of different genotypes. Average maintenance LTG doses in the responder group differed by genotype in the order AA>GA>GG, but these differences did not reach statistical significance. Conclusion: Our data suggest lack of association between SCN1A IVS5-91G>A (rs3812718) polymorphism and response to LTG.
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TMS as a pharmacodynamic indicator of cortical activity of a novel anti-epileptic drug, XEN1101.
Premoli, I, Rossini, PG, Goldberg, PY, Posadas, K, Green, L, Yogo, N, Pimstone, S, Abela, E, Beatch, GN, Richardson, MP
Annals of clinical and translational neurology. 2019;(11):2164-2174
Abstract
OBJECTIVE Transcranial magnetic stimulation (TMS) produces characteristic deflections in the EEG signal named TMS-evoked EEG potentials (TEPs), which can be used to assess drug effects on cortical excitability. TMS can also be used to determine the resting motor threshold (RMT) for eliciting a minimal muscle response, as a biomarker of corticospinal excitability. XEN1101 is a novel potassium channel opener undergoing clinical development for treatment of epilepsy. We used TEPs and RMT to measure the effects of XEN1101 in the human brain, to provide evidence that XEN1101 alters cortical excitability at doses that might be used in future clinical trials. METHODS TMS measurements were incorporated in this Phase I clinical trial to evaluate the extent to which XEN1101 modulates TMS parameters of cortical and corticospinal excitability. TEPs and RMT were collected before and at 2-, 4-, and 6-hours post drug intake in a double-blind, placebo-controlled, randomized, two-period crossover study of 20 healthy male volunteers. RESULTS Consistent with previous TMS investigations of antiepileptic drugs (AEDs) targeting ion channels, the amplitude of TEPs occurring at early (15-55 msec after TMS) and at late (150-250 msec after TMS) latencies were significantly suppressed from baseline by 20 mg of XEN1101. Furthermore, the RMT showed a significant time-dependent increase that correlated with the XEN1101 plasma concentration. INTERPRETATION Changes from baseline in TMS measures provided evidence that 20 mg of XEN1101 suppressed cortical and corticospinal excitability, consistent with the effects of other AEDs. These results support the implementation of TMS as a tool to inform early-stage clinical trials.
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The Lack of Effect of Food on the Pharmacokinetics of ZX008 (Fenfluramine Oral Solution): Results of a Single-dose, Two-period Crossover Study.
Gammaitoni, A, Smith, S, Boyd, B
Clinical therapeutics. 2018;(8):1338-1346
Abstract
PURPOSE Fenfluramine is being developed as a low-dose adjunctive treatment for seizures in patients with Dravet syndrome and other epileptic encephalopathies, including Lennox-Gastaut syndrome. Most patients with Dravet syndrome receive multiple antiepileptic drugs, making it challenging for caregivers to track correct administration times. The present Phase I study was conducted to determine the effect of food on the pharmacokinetic properties of fenfluramine. METHODS Healthy nonsmoking subjects aged 18 to 50 years were enrolled in an open-label, crossover, Phase I pharmacokinetic and safety profile study and received 2 single 0.8-mg/kg doses of ZX008 (fenfluramine hydrochloride oral solution), 1 after a 10-hour overnight fast and the other 30 minutes after the start of consumption of a high-fat breakfast, in a randomly assigned order. A washout period of at least 9 days separated the 2 treatment periods. Venous blood samples were taken before each dose and periodically for 72 hours after each dose for determination of concentrations of fenfluramine and its active metabolite norfenfluramine. Plasma pharmacokinetic parameters were estimated for each subject by noncompartmental analysis. FINDINGS In the 13 subjects completing both treatment periods, food had no effect on the rate or extent of absorption and bioavailability of fenfluramine as assessed by fed vs fasted adjusted geometric mean observed plasma Cmax (59.1 vs 56.7 ng/mL; NS) and AUC0-∞ (1640 vs 1600 ng · h/mL; NS). Additionally, there was no impact of food on systemic exposure of norfenfluramine. Seven subjects reported at least 1 treatment-emergent adverse event; all treatment-emergent adverse events were mild in severity. IMPLICATIONS The bioequivalence and tolerability of single 0.8-mg/kg oral doses of ZX008 in the fed and fasted states support ZX008 administration without regard to meals.
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Tolerability of adjunctive eslicarbazepine acetate according to concomitant lamotrigine or carbamazepine use: A subgroup analysis of three phase III trials in adults with focal (partial-onset) seizures.
Abou-Khalil, B, Klein, P, Shah, A, Ryvlin, P, Specchio, LM, Gama, H, Rocha, F, Blum, D, Grinnell, T, Cheng, H, et al
Epilepsy research. 2018;:80-86
Abstract
OBJECTIVE To evaluate and compare the effects of concomitant lamotrigine (LTG) or carbamazepine (CBZ) on the incidence of treatment-emergent adverse events (TEAEs) in patients taking adjunctive eslicarbazepine acetate (ESL) for focal (partial-onset) seizures (FS). METHODS These post-hoc analyses of data pooled from three randomized, double-blind, placebo-controlled studies of adjunctive ESL (BIA-2093-301, -302 and -304) included adults (≥16 years) with FS refractory to 1-3 antiepileptic drugs (AEDs). Patients were randomized equally to placebo, ESL 400 mg (Studies 301 and 302 only), 800 mg, or 1200 mg once daily (8-week baseline, 2-week titration, and 12-week maintenance periods). TEAEs, TEAEs leading to discontinuation, and serious AEs (SAEs) were evaluated in patients taking, or not taking, LTG (excluding those taking CBZ or phenytoin [PHT]; i.e., the +LTG and -LTG/-CBZ subgroups), or CBZ (excluding those taking LTG or PHT; i.e., the +CBZ and -LTG/-CBZ subgroups) at baseline. RESULTS LTG was used concomitantly by 248 patients (+LTG; placebo, n = 81; ESL, n = 167) and CBZ by 613 patients (+CBZ; placebo, n = 172; ESL, n = 441); 361 patients were taking neither LTG nor CBZ (-LTG/-CBZ; placebo, n = 109; ESL, n = 252). The overall incidence of TEAEs with ESL (any dose) was numerically higher for +CBZ (77%) than for +LTG (73%) or -LTG/-CBZ (68%; statistical significance not tested). Among patients taking ESL, dizziness, diplopia, and vomiting were reported more frequently in the +CBZ subgroup (30%, 14%, and 10%, respectively) than in the +LTG (16%, 8%, 5%) or -LTG/-CBZ (11%, 3%, 5%) subgroups. The overall incidence of TEAEs leading to discontinuation with ESL was higher for +CBZ (21%) than for +LTG (13%) or -LTG/-CBZ (15%). Dizziness leading to discontinuation with ESL was reported more frequently in the +CBZ subgroup than in the +LTG or -LTG/-CBZ subgroups (9%, 3%, and 3%, respectively). The overall incidence of SAEs in patients taking ESL was comparable across subgroups (+LTG, 5%; +CBZ, 6%; -LTG/-CBZ, 5%). The results were similar when evaluating placebo-adjusted incidences. CONCLUSION There was a potential pharmacodynamic interaction between AEDs with a putatively similar mechanism of action, with a seemingly lesser interaction between ESL and LTG versus ESL and CBZ. If combining ESL with LTG or CBZ, clinicians should be aware of the potential risk for an increased incidence of TEAEs typically associated with voltage-gated sodium channel inhibitors (e.g., dizziness, blurred vision, vertigo, diplopia, headache, or vomiting).
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A pilot study of add-on oral triheptanoin treatment for children with medically refractory epilepsy.
Calvert, S, Barwick, K, Par, M, Ni Tan, K, Borges, K
European journal of paediatric neurology : EJPN : official journal of the European Paediatric Neurology Society. 2018;(6):1074-1080
Abstract
AIM: Despite antiepileptic medication and dietary treatment options available about 45% of children with epilepsy still suffer from uncontrolled seizures. Triheptanoin is an anaplerotic treatment designed to improve energy generation via the Krebs cycle. METHOD For the first time, we evaluated the feasibility, tolerability and efficacy of add-on triheptanoin in 12 patients with medically refractory epilepsy (seven males, five females; min-max: 3-18yr, median 13.5 yr). RESULTS Eight out of a total of 12 children (67%), who tested the treatment, finished the trial and tolerated between 30 and 100 ml of triheptanoin per day for >12 weeks (median 55 ml, 20.5% caloric intake). The most common adverse effects were diarrhea and other gastro-intestinal effects in seven kids. One child experienced leaking and another child had an infected percutaneous endoscopic gastrostomy button. Five children (62.5%), who all had been on the ketogenic diet previously, showed sustained >50% reductions in seizure frequency, including one patient who became seizure free for 30 weeks. Four patients extended their treatment to a total of 201-909 days, until seizure frequency or severity increased. INTERPRETATION In this small trial, triheptanoin was safe and tolerable in children with epilepsy. As some children showed reductions in seizure numbers and/or severity, larger randomized controlled studies are now needed for further evaluation of safety and efficacy.
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Clinical features of benign epilepsy of childhood with centrotemporal spikes in chinese children.
Liu, MJ, Su, XJ, Md, XS, Wu, GF, Zhang, YQ, Gao, L, Wang, W, Liao, JX, Wang, H, Mai, JN, et al
Medicine. 2017;(4):e5623
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Abstract
This multicenter clinical trial was conducted to examine current practice of benign epilepsy with centrotemporal spikes and especially address the question that in what circumstances 1 antiepileptic drug (AED) should be preferred.Twenty-five medical centers participate in this clinical trial. The general information, clinical information, and treatment status were collected under the guidance of clinicians and then analyzed. Difference between different treatment groups was compared, and usefulness of the most commonly used AEDs was evaluated.A total of 1817 subjects were collected. The average age of the subject was 8.81 years. The average age of onset is 6.85 years (1-14 years). Male-to-female ratio is 1.13:1. A total of 62.9% of the patients are receiving monotherapies, and 10.6% are receiving multidrug therapy. Both age and course of disease of treated rolandic epilepsy (RE) patients are significantly different from those of untreated patients. Bilateral findings on electroencephalography (EEG) are less seen in patients with monotherapy compared with patients with multidrug therapy. Except for 25.4% patients not taking any AEDs, oxcarbazepine (OXC), sodium valproate (VPA), and levetiracetam (LEV) are the most commonly used 3 AEDs. VPA and LEV are commonly used in add-on therapy. OXC and LEV are more effective as monotherapy than VPA.Age of onset of Chinese RE patients is 6.85 years. Bilateral findings on EEG could be a risk factor to require multidrug therapy. In Chinese patients, OXC, VPA, and LEV are most commonly used AEDs as monotherapy and OXC and LEV are more effective than VPA.
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Changes in hormone and lipid levels in male patients with focal seizures when switched from carbamazepine to lacosamide as adjunctive treatment to levetiracetam: A small phase IIIb, prospective, multicenter, open-label trial.
Elger, CE, Rademacher, M, Brandt, C, Elmoufti, S, Dedeken, P, Eckhardt, K, Tennigkeit, F, De Backer, M
Epilepsy & behavior : E&B. 2016;:1-5
Abstract
Treatment with enzyme-inducing antiepileptic drugs (AEDs) such as carbamazepine (CBZ) can lead to changes in reproductive, endocrine, and lipid parameters, resulting in clinical symptoms for some patients. Previous studies indicate that these changes can be reversed by switching to a nonenzyme-inducing AED. Lacosamide is a newer-generation AED, not known to induce or strongly inhibit cytochrome P450 (CYP450) enzymes. In this phase IIIb, prospective, multicenter, open-label, single-arm trial (NCT01375374), the serum concentrations of CYP-related reproductive hormones, thyroid hormones, and lipids were assessed in otherwise healthy male patients with focal seizures (N=11), before and after a switch from CBZ (600-1200mg/day at baseline) to lacosamide (target dose: 400mg/day by the end of titration) as adjunctive treatment to the nonenzyme-inducing AED levetiracetam (LEV, stable dosage of >1000mg/day throughout). Cross titration took place over 4weeks, followed by an 8-week maintenance period. Serum measurements were conducted at baseline and at the end of maintenance. The median serum sex-hormone-binding globulin (SHBG) concentration was towards the higher end of the normal range at baseline and decreased following the switch (61.7 to 47.5nmol/L, N=10, p=0.027 by Wilcoxon signed-rank test). Free androgen index (100×testosterone/SHBG) and free thyroxine serum concentration increased (25.4 to 36.4 and 13.0 to 14.9pmol/L, respectively, both N=10 and p=0.002). At baseline, the median progesterone serum concentration was below the normal range (0.7nmol/L), whereas median cholesterol and low-density lipoprotein concentrations were above the normal range (5.5 and 3.6mmol/L, respectively). By the end of maintenance, all measured parameters were within the normal range. The safety and tolerability profile of lacosamide was consistent with that observed in previous studies. Furthermore, antiseizure efficacy appeared to be maintained, suggesting that deinduction of CYP enzymes following a switch from CBZ to lacosamide as adjunctive therapy to LEV is feasible within 8weeks and is associated with normalization of serum parameters.