Pharmacokinetic Variability of Rufinamide and Stiripentol in Children With Refractory Epilepsy: A Retrospective Study of Therapeutic Drug Monitoring From the National Epilepsy Centers in Denmark and Norway.

BACKGROUND: Rufinamide and stiripentol, orphan drugs used in Lennox-Gastaut and Dravet syndromes, respectively, are antiseizure medications (ASMs), often administered to children; however, pharmacokinetic studies are lacking. The authors compared the pharmacokinetic variability of these drugs with respect to the dose, serum concentrations, comedication, age, and duration of treatment. METHODS: Children and adolescents (<18 years) whose serum concentrations were measured were retrospectively identified from the therapeutic drug monitoring (TDM) databases at 2 national epilepsy centers in Norway and Denmark (2012-2021). RESULTS: Data from 165 patients (56% boys/44% girls) treated with rufinamide and 52 patients (50% boys/50% girls) treated with stiripentol were included. For rufinamide, the median age was 10 (range 2-17) years, dose 23 (3-73) mg/d, and serum concentration 34 (3-227) µmol/L [8.1 mg/L (0.71-54.0 mg/L)]. For stiripentol, the median age was 8.5 (range 1-17) years, dose 37 (18-76) mg/d, and serum concentration 33 (4-113) µmol/L [7.7 mg/L (0.93-26.3 mg/L)]. The concomitant use of 1-9 other ASMs during the data collection was noted. Pharmacokinetic variability, calculated as the concentration/(dose/kg) ratio, ranged from 0.26 to 11.31 (µmol/L)/(mg/kg) for rufinamide and 0.17-1.52 (µmol/L)/(mg/kg) for stiripentol. The intraindividual coefficients of variation ranged widely, from 5% to 110% for rufinamide and 11%-117% for stiripentol. The treatment period was at least 5 years in 50% of patients. No statistically significant effects of age, sex, or ASM comedication were observed, possibly due to the small sample size and heterogeneous groups with variable seizure situations, comorbidities, and changes in comedication and physiology. CONCLUSIONS: This study demonstrates considerable pharmacokinetic variability in and between patients for both drugs and similar use in terms of age, burden of comedication and retention rates. TDM may be useful in the clinical setting to monitor and optimize treatment in this vulnerable patient group.

Dysregulated Apoptosis and Autophagy in Childhood Epilepsy: Correlation to Clinical and Pharmacological Patterns.

OBJECTIVES: We aimed to assess the serum levels of caspase-3 as a marker of apoptosis and microtubule-associated protein 1A/1B-light chain 3 (MAP1-LC3) as an autophagy marker in epileptic children with various clinical and pharmacological types. METHODS: This case-control study was carried out on 90 participants (50 pediatric patients with epilepsy and 40 healthy matched children), the patients were categorized into three groups: Group (A): 25 pharmacosensitive epilepsy, Group (B): 25 pharmacoresistant epilepsy, and Group (C): 40 (age, sex, and body mass index) matched healthy children selected as controls. Serum caspase-3 and MAP1-LC3 were measured in all study groups, using commercially available ELISA kits. RESULTS: Serum caspase-3 was significantly higher among epileptic children, especially in the pharmacoresistant group, cases managed with multiple antiepileptic drugs, and cases with abnormal EEG findings. Conversely, circulating MAP1-LC3 levels showed a significant reduction in epilepsy cases, particularly in pharmacoresistant cases, in cases treated with multiple antiepileptic drugs, and in cases with abnormal EEG data. A significant negative correlation between serum caspase-3 and MAP1-LC3 was found among epileptic children (r = -0.369, p = 0.0083). Serum caspase-3 was a more valid biomarker in helping diagnose childhood epilepsy, while serum MAP1-LC3 was more valid in predicting pharmacoresistant type. CONCLUSION: The study reveals that serum caspase-3 levels were significantly elevated, particularly in pharmacoresistant cases and those managed with multiple drugs. Conversely, MAP1-LC3 levels were significantly reduced in epilepsy cases, suggesting potential involvement of altered apoptosis and autophagy in childhood epilepsy.

Evaluating the serum levels of zinc, copper, magnesium, and 25-hydroxy vitamin D in children with idiopathic drug-resistant epilepsy; a cross-sectional study.

BACKGROUND: Drug-resistant epilepsy is defined as failure of seizure control in spite of using 2 or 3 proper antiepileptic drugs in appropriate time. Mineral elements play important roles in neuronal function; it is believed that mineral deficiency may lead to complications through seizure management. In the present study, serum levels of zinc (Zn), copper (Cu), magnesium (Mg), calcium (Ca), and 25-hydroxy vitamin D (Vit D) in drug-resistant-epilepsy (DRE) patients were evaluated and compared with the controlled patients. METHODS: In this cross-sectional study, epileptic patients were included and categorized into two groups of DRE and well-controlled patients. Patients' serum samples were analysed to evaluate Zn, Cu, Mg, Ca, and Vit D levels. The primary objective was comparison of serum levels of different trace elements between the groups. RESULTS: Sixty-four epileptic children including 33 DRE and 31 well-controlled children entered the study. The DRE children showed a significantly earlier onset of disease compared to the other group (p = 0.014). Comparing the frequency of developmental delay between the groups, the results showed this complication was significantly more frequent in the DRE group (p < 0.001). Concerning serum elements, the results showed a significantly higher concentration of Zn in the well-controlled group than the DRE group (p = 0.007). On the other hand, no significant differences were observed between the groups regarding the means of Vit D, Ca, Cu, and Mg levels (p > 0.05). CONCLUSION: The results of the present study delineated that drug-resistant epilepsy patients had earlier onset of disease and were at higher risk of neurodevelopmental delay compared with well-controlled-epilepsy patients. A significant lower serum levels of Zn were also observed in drug-resistant-epilepsy patients. This finding may suggest the role of zinc supplementation in help to better control of drug-resistant seizures, as well as, the importance of serum zinc monitoring in epileptic patients.

Evaluation of IL-10, IFN-γ, and thiol-disulfide homeostasis in patients with drug-resistant epilepsy.

AIM: This study compared dynamic thiol-disulfide homeostasis (an oxidative stress marker), anti-inflammatory interleukin-10 (IL-10) levels, and proinflammatory interferon gamma (IFN-γ) levels in drug-resistant epilepsy patients with those in patients with well-controlled epilepsy and healthy controls. METHOD: This prospective cross-sectional study enrolled 89 people: 27 with drug-resistant epilepsy, 30 with well-controlled epilepsy, and 32 healthy controls matched in demographic characteristics. RESULTS: The mean serum IL-10 levels were significantly lower and the mean serum IFN-γ levels significantly higher in the drug-resistant epilepsy patients compared to the well-controlled epilepsy and healthy control groups. The mean serum native thiol (SH) and total thiol (TT) levels were significantly lower, and the disulfide (SS) levels were significantly higher in the drug-resistant group than in the other two groups. CONCLUSIONS: The significant differences in thiol-disulfide homeostasis and IL-10 and IFN-γ levels in the drug-resistant epilepsy group suggest that these markers indicate a poor prognosis in epilepsy.

Chronically reduced IL-10 plasma levels are associated with hippocampal sclerosis in temporal lobe epilepsy patients.

BACKGROUND: Increasing evidence supports the role of soluble inflammatory mediators in the pathogenesis of refractory temporal lobe epilepsy (TLE). Hippocampal sclerosis (HS) is a well-described pathohistological abnormality in TLE. The association of proinflammatory cytokines with epileptic disease profiles is well established; however, the potential significance of circulating interleukin 10 (IL-10), particularly in TLE-associated HS, is still poorly understood. Therefore, taking into consideration the neuroprotective and anticonvulsive effects of IL-10, we performed this study to examine the role of the plasma levels of IL-10 in patients with TLE with HS (TLE + HS), TLE without HS (TLE-HS) and with other types of epilepsy. METHODS: This study included 270 patients with refractory epilepsy who were classified into four groups: i) 34 patients with TLE + HS, ii) 105 patients with TLE-HS, iii) 95 patients with extra-TLE (XLE) and iv) 36 patients with idiopathic generalized epilepsy (IGE). The plasma IL-10 levels were quantified using a commercially available enzyme-linked immunosorbent assay (ELISA). RESULTS: IL-10 levels were significantly lower in TLE + HS than in TLE-HS (p = 0.013). In a subgroup of TLE-HS patients who had seizures 1 month before sampling, patients with seizures had significantly higher IL-10 levels than patients who were seizure-free (p = 0.039). Among a small group (n = 15) of non-refractory TLE-HS patients, IL-10 levels showed a moderate negative correlation with the duration of epilepsy (r = - 0.585, p = 0.023). CONCLUSIONS: This study demonstrated that chronically reduced levels of plasma IL-10 were associated with HS in TLE patients, suggesting that there was an inadequate systemic anti-inflammatory immune response. These results could provide new biological insights into the pathophysiology of HS in TLE. We also found that the production of IL-10 could be affected by the seizure frequency and declined concomitantly with increased disease durations. Therefore, the measurement of plasma IL-10 may have diagnostic value as a biomarker for stratifying TLE + HS from other epilepsy types or as a marker of disease progression towards a progressive form of epilepsy.

Effects of modified Atkins diet on thyroid function in adult patients with pharmacoresistant epilepsy.

INTRODUCTION: The use of ketogenic diet as a supplement to antiseizure medication (ASM) in refractory epilepsy has increased the past decades. This high-fat, low-carbohydrate diet mimics the metabolic state of fasting and is generally well-tolerated. However, the long-term adverse effects of the diet are unclear. The purpose of this study was to investigate whether the modified Atkins diet (MAD), a variant of the ketogenic diet, may have an impact on thyroid hormone levels. METHODS: We assessed thyroid function by measuring thyroid stimulation hormone (TSH), fT4, T3, fT3, and rT3 before diet start (baseline) and after 12 weeks on the diet in 53 adult patients with drug-resistant epilepsy. Further, we examined the correlation between the changes in thyroid function during dietary treatment and type of (i) change in seizure frequency, (ii) drugs in use, and (iii) degree of ketosis. RESULTS: After 12 weeks on the diet, we found a significant reduction in T3 and fT3 values (13.4% and 10.6%, respectively) and a significant increase in fT4 values (12.1%) compared with baseline. In addition, there was an insignificant increase in TSH and rT3. These changes were similar in women and men, and there was no correlation to drugs in use (enzyme-inducing vs. nonenzyme-inducing drugs), changes in seizure frequency, or level of ketosis. CONCLUSION: This study indicates that dietary treatment for epilepsy may bring about a modest fall in thyroid hormone levels. This could be relevant for those patients with low thyroid hormones and those treated with ASMs known to lower thyroid hormone levels. A cumulative effect of ASMs, low basal thyroid hormone levels, and ketogenic diet may therefore be of clinical importance in the case of thyroid hormones when treating patients with MAD.

Chronic vagus nerve stimulation for drug-resistant epilepsy may influence fasting blood glucose concentration.

BACKGROUND: Cervical vagus nerve stimulation (VNS) has been widely accepted as adjunctive therapy for drug-resistant epilepsy and major depression. Its effects on glycemic control in humans were however poorly understood. The aim of our study was to investigate the potential effects of VNS on fasting blood glucose (FBG) in patients with drug-resistant epilepsy. METHODS: Patients with drug-resistant epilepsy who had received VNS implants at the same hospital were retrospectively studied. Effects on FBG, weight, body mass index and blood pressure were evaluated at 4, 8 and 12 months of follow-up. RESULTS: 32 subjects (11 females/21 males, 19 ± 9 years, body mass index 22.2 ± 4.0 kg/m2) completed 12-month follow-up. At the 4 months, there were no significant changes in FBG concentrations from baseline to follow-up in both Sham-VNS (4.89 ± 0.54 vs. 4.56 ± 0.54 mmol/L, N = 13, p = 0.101) and VNS (4.80 ± 0.54 vs. 4.50 ± 0.56 mmol/L, N = 19, p = 0.117) groups. However, after 8 (4.90 ± 0.42 mmol/L, N = 32, p = 0.001) and 12 (4.86 ± 0.40 mmol/L, N = 32, p = 0.002) months of VNS, FBG levels significantly increased compared to baseline values (4.52 ± 0.54 mmol/L, N = 32). Changes in FBG concentrations at both 8 (R2 = 0.502, N = 32, p < 0.001) and 12 (R2 = 0.572, N = 32, p < 0.001) months were negatively correlated with baseline FBG levels. CONCLUSIONS: Our study suggests that chronic cervical VNS elevates FBG levels with commonly used stimulation parameters in patients with epilepsy. Trial registration VNSRE, NCT02378792. Registered 4 March 2015-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02378792.

Tocilizumab treatment for new onset refractory status epilepticus.

We investigated the therapeutic potential of the interleukin-6 receptor inhibitor tocilizumab in 7 patients with new onset refractory status epilepticus (NORSE) who remained refractory to conventional immunotherapy with rituximab (n = 5) or without rituximab (n = 2). Status epilepticus (SE) was terminated after 1 or 2 doses of tocilizumab in 6 patients with a median interval of 3 days from the initiation. They had no recurrence of SE during the observation. However, 2 patients experienced severe adverse events related to infection during the tocilizumab therapy. Further prospective controlled studies are warranted to validate the efficacy and safety of tocilizumab in patients with NORSE. Ann Neurol 2018;84:940-945.

Pharmacokinetic interaction between modified Atkins diet and antiepileptic drugs in adults with drug-resistant epilepsy.

OBJECTIVE: The aim was to examine the influence of modified Atkins diet on serum concentration of antiepileptic drugs (AEDs). METHODS: Prospective data from 63 adult patients with either focal or generalized drug-resistant epilepsy recruited to 12-week dietary treatment as add-on to AEDs are analyzed. AED serum concentrations, ketones, glucose, and hemoglobin A1c were measured before and after the dietary intervention. Paired t test was used and Spearman correlation coefficient, r, was estimated. RESULTS: Mean age was 37 years (range 16-65 years). Mean serum concentrations of carbamazepine, clobazam, and valproate were significantly reduced after 4 and 12 weeks of the diet period (<.001 ≤ P ≤ .02). Levels of lacosamide, lamotrigine, and topiramate were less reduced (.02 ≤ P ≤ .08), whereas the serum concentrations of oxcarbazepine, zonisamide, and levetiracetam were unchanged (.06 ≤ P ≤ .90). The largest reduction in serum concentration was found for clobazam: mean reduction after 12 weeks was 1.5 µmol/L (34%). Percent change in serum concentration after 4 and 12 weeks of all drugs analyzed was -10.5% (95% confidence interval [CI] -14.1 to -6.8; n = 60; P < .001) and -13.5% (95% CI -18.8 to -8.3; n = 56; P < .001), respectively. Percent change in serum concentration of AEDs was not significantly correlated to percent change in seizure frequency after 12 weeks of dietary treatment (r = .14, P = .33, n = 53) but negatively correlated to urine ketosis (r = -.43; P = .003; n = 46). SIGNIFICANCE: A reduction in AED serum concentrations may counteract a seizure-reducing effect of the diet, and in patients without such an effect, it may cause seizure aggravation. Thus, we recommend that clinicians who are treating patients with ketogenic diets monitor serum concentrations of the concomitant AEDs.

Higher cannabidiol plasma levels are associated with better seizure response following treatment with a pharmaceutical grade cannabidiol.

OBJECTIVE: The objective of this study was to determine the relationship between cannabidiol (CBD) dose, CBD plasma level, and seizure control in a large open-label single-center study. METHODS: All participants with treatment-refractory epilepsy participating in our expanded access program (EAP) were approached for participation. Highly purified grade CBD (Epidiolex®) dosing was weight-based and could be increased every 2 weeks by 5 mg/kg/day up to a maximum dosage of 50 mg/kg/day depending on tolerance and seizure control. Seizure counts were obtained at each visit with frequency calculated per 2-week periods. Cross-sectional plasma peak levels of CBD were obtained ~4 h after dosing in consecutively presenting patients. RESULTS: We evaluated 56 adults and 44 children (100 total; 54 female) at two time points - one before initiating CBD and one at the time of CBD plasma level testing. There was a positive linear correlation between CBD dosage (range from 5 to 50 mg/kg/day) and level (range from 7.1-1200 ng/mL) in all participants (r = 0.640; p < 0.001). The quantile regression model supported the notion of increased CBD levels being associated with improvement in seizure frequency after adjusting for age - specifically, a 100 ng/mL increase in CBD level was associated with approximately two counts reduction in seizure frequency per time period (1.87 96% confidence interval [CI] 0.34-3.39; p = 0.018). In participants with the same CBD level, differences in seizure improvement did not depend on age (p = 0.318). CONCLUSIONS: In this open-label study, we found evidence of a linear correlation between CBD dosage and plasma levels, and that higher dose/levels are associated with a higher response rate for seizure improvement. Children and adults responded to CBD similarly. However, seizure control response rates suggest children may respond to lower dosages/plasma levels than adults. Findings reported in this study are specific to Epidiolex® and should not be extrapolated to other CBD products.

Follow-up of patients with epilepsy harboring antiglycine receptor antibodies.

OBJECTIVE: The long-term follow-up of patients with epilepsy harboring autoantibodies against the glycine receptor (also glycine receptor antibodies or GlyR-Ab) is not well-known. Our aim was to investigate the 5-year prognosis and treatment response of patients with epilepsy who were seropositive for GlyR-Ab. METHODS: Clinical features; electroencephalogram (EEG), neuroradiological, and neuropathological findings; and treatment responses of patients with epilepsy with GlyR-Ab seropositivity were investigated. RESULTS: Thirteen (5.46%) of 238 patients with epilepsy were GlyR-Ab positive: focal epilepsy of unknown cause (FEoUC) was diagnosed in four (7.27%) out of 55 patients, mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) in five (4.5%) out of 111 patients, epileptic encephalopathy (EE) in two (4%) out of 50 patients, and status epilepticus (SE) in two (9.09%) out of 22 patients. None of the patients developed any other neurological symptoms or cancer during the 5-year follow-up. Seven of them had seizures that were resistant to antiepileptic drug (AED). Immunotherapy was used in two patients (with FEoUC and EE) improving seizure control. Three patients with MTLE-HS benefited from epilepsy surgery, and another patient with EE showed spontaneous remission. CONCLUSION: Glycine receptor antibodies are detected in a wide spectrum of epileptic disorders with unclear pathogenic significance. Two GlyR-Ab seropositive patients with AED-resistant epilepsy treated with intravenous immunoglobulin (IVIg) showed clear benefit from immunotherapy. Future studies will be valuable in determining the role of screening patients with drug-resistant epilepsy for GlyR-Ab in order to identify patients who may benefit or respond to immunotherapy.

A novel action of lacosamide on GABAA currents sets the ground for a synergic interaction with levetiracetam in treatment of epilepsy.

Epilepsy is one of the most common chronic neurological diseases, and its pharmacological treatment holds great importance for both physicians and national authorities, especially considering the high proportion of drug-resistant patients (about 30%). Lacosamide (LCM) is an effective and well-tolerated new-generation antiepileptic drug (AED), currently licensed as add-on therapy for partial-onset seizures. However, LCM mechanism of action is still a matter of debate, although its effect on the voltage sensitive sodium channels is by far the most recognized. This study aimed to retrospectively analyze a cohort of 157 drug-resistant patients treated with LCM to describe the most common and effective therapeutic combinations and to investigate if the LCM can affect also GABAA-mediated neurotransmission as previously shown for levetiracetam (LEV). In our cohort, LEV resulted the compound most frequently associated with LCM in the responder subgroup. We therefore translated this clinical observation into the laboratory bench by taking advantage of the technique of "membrane micro-transplantation" in Xenopus oocytes and electrophysiological approaches to study human GABAA-evoked currents. In cortical brain tissues from refractory epileptic patients, we found that LCM reduces the use-dependent GABA impairment (i.e., "rundown") that it is considered one of the specific hallmarks of drug-resistant epilepsies. Notably, in line with our clinical observations, we found that the co-treatment with subthreshold concentrations of LCM and LEV, which had no effect on GABAA currents on their own, reduced GABA impairment in drug-resistant epileptic patients, and this effect was blocked by PKC inhibitors. Our findings demonstrate, for the first time, that LCM targets GABAA receptors and that it can act synergistically with LEV, improving the GABAergic function. This novel mechanism might contribute to explain the clinical efficacy of LCM-LEV combination in several refractory epileptic patients.

Systemic autoinflammation with intractable epilepsy managed with interleukin-1 blockade.

BACKGROUND: Autoinflammatory disorders are distinguished by seemingly random episodes of systemic hyperinflammation, driven in particular by IL-1. Recent pre-clinical work has shown a key role for IL-1 in epilepsy in animal models, and therapies for autoinflammation including IL-1 blockade are proposed for refractory epilepsy. CASE PRESENTATION: Here, we report an adolescent female with signs of persistent systemic inflammation and epilepsy unresponsive to multiple anti-epileptic drugs (AED). She was diagnosed with generalized epilepsy with a normal brain MRI and an electroencephalogram (EEG) showing occasional generalized spike and slow wave discharges. Her diagnostic evaluation showed no signs of autoimmunity or genetic causes of epilepsy or periodic fever syndromes but persistently elevated serum inflammatory markers including S100 alarmin proteins. She experienced prompt clinical response to IL-1 blockade with first anakinra and then canakinumab, with near complete resolution of clinical seizures. Additionally, she displayed marked improvements in quality of life and social/academic functioning. Baseline gene expression studies on peripheral blood mononuclear cells (PBMC) from this patient showed significantly activated gene pathways suggesting systemic immune activation, including focal adhesion, platelet activation, and Rap1 signaling, which is an upstream regulator of IL-1ß production by the NLRP3 inflammasome. It also showed activation of genes that characterize inflammasome-mediated autoinflammatory disorders and no signs of interferon activation. This gene expression signature was largely extinguished after anakinra treatment. CONCLUSIONS: Together, these findings suggest that patients with epilepsy responsive to immune modulation may have distinct autoinflammatory features supporting IL-1 blockade. As such, IL-1 blockade may be highly efficacious adjunctive medication for certain refractory epilepsy syndromes.

Analysis of hematological parameters in patients treated with ketogenic diet due to drug-resistant epilepsy.

Benefits of the ketogenic diet (KD) in epileptic patients are well known while less is known about the nutritional risks of the diet and its potential impacts on biochemical nutritional status. In this study, we aimed to evaluate the hematological parameters of patients who have drug-resistant epilepsy and are treated with KD. Fifty-three patients with drug-resistant epilepsy (mean age 7.4 ± 4.4 years [2-18], 23 [43.4%] female) were included in the study. Demographic and laboratory data of the patients were retrospectively analyzed at baseline and Month 6 and Month 12 of the treatment. Repeated measures ANOVA (post hoc Bonferroni correction) and Friedman test were used to assess the changes in data during the treatment. Mean hemoglobin levels increased by 0.594 g/dL after 6 months (p = 0.001) and by 0.602 g/dL after 12 months of the treatment (p = 0.002). Mean hematocrit level was found to be significantly increased at Month 6 and 12 of the treatment compared to baseline [F(2,94) = 8.9, p < 0.0001]. An increase in MCV levels was determined with the KD treatment [F(2,94) = 19.7, p < 0.0001]. Mean level of vitamin B12 was found to be significantly increased in Month 12 of treatments compared to Month 6 [F(1.686,72.479) = 3.472, p = 0.035]. There was no significant effect of KD on other hematological parameters (red blood cell, white blood cell and platelet counts, serum iron, total iron-binding capacity, transferrin saturation, and ferritin and folic acid levels). We can conclude that KD increases levels of hemoglobin, hematocrit, MCV, and serum vitamin B12 in patients with intractable epilepsy. Prospective, multi-center, longitudinal studies are needed to confirm our results.

The protocol for the Cannabidiol in children with refractory epileptic encephalopathy (CARE-E) study: a phase 1 dosage escalation study.

BACKGROUND: Initial studies suggest pharmaceutical grade cannabidiol (CBD) can reduce the frequency of convulsive seizures and lead to improvements in quality of life in children affected by epileptic encephalopathies. With limited access to pharmaceutical CBD, Cannabis extracts in oil are becoming increasingly available. Physicians show reluctance to recommend Cannabis extracts given the lack of high quality safety data especially regarding the potential for harm caused by other cannabinoids, such as Δ9-tetrahydrocannabinol (Δ9-THC). The primary aims of the study presented in this protocol are (i) To determine whether CBD enriched Cannabis extract is safe and well-tolerated for pediatric patients with refractory epilepsy, (ii) To monitor the effects of CBD-enriched Cannabis extract on the frequency and duration of seizure types and on quality of life. METHODS: Twenty-eight children with treatment resistant epileptic encephalopathy ranging in age from 1 to 10 years will be recruited in four Canadian cities into an open-label, dose-escalation phase 1 trial. The primary objectives for the study are (i) To determine if the CBD-enriched Cannabis herbal extract is safe and well-tolerated for pediatric patients with treatment resistant epileptic encephalopathy and (ii) To determine the effect of CBD-enriched Cannabis herbal extract on the frequency and duration of seizures. Secondary objectives include (i) To determine if CBD-enriched Cannabis herbal extracts alter steady-state levels of co-administered anticonvulsant medications. (ii) To assess the relation between dose escalation and quality of life measures, (iii) To determine the relation between dose escalation and steady state trough levels of bioactive cannabinoids. (iv) To determine the relation between dose escalation and incidence of adverse effects. DISCUSSION: This paper describes the study design of a phase 1 trial of CBD-enriched Cannabis herbal extract in children with treatment-resistant epileptic encephalopathy. This study will provide the first high quality analysis of safety of CBD-enriched Cannabis herbal extract in pediatric patients in relation to dosage and pharmacokinetics of the active cannabinoids. TRIAL REGISTRATION: http://clinicaltrials.gov [Internet]. Bethesda (MD): National Library of Medicine (US). 2016 Dec 16. Identifier NCT03024827, Cannabidiol in Children with Refractory Epileptic Encephalopathy: CARE-E; 2017 Jan 19 [cited 2017 Oct]; Available from: http://clinicaltrials.gov/ct2/show/NCT03024827.

Therapeutic Drug Monitoring of Lacosamide in Norway: Focus on Pharmacokinetic Variability, Efficacy and Tolerability.

Lacosamide (LCM) is a new antiepileptic drug (AED). Experience from therapeutic drug monitoring (TDM) in clinical practice is limited. The purpose of this study is to evaluate the pharmacokinetic variability of LCM in relation to efficacy and tolerability in patients with refractory epilepsy in a real-life setting. Variables included age, gender, daily doses and serum concentrations of LCM and other AEDs from the TDM-database at the National Center for Epilepsy in Norway. Clinical data regarding efficacy and tolerability were collected from medical records. The Norwegian Prescription Database (NorPD) was used to include population-based numbers of users. TDM-data from 344 patients were included. The median dose, serum concentration, and concentration/dose (C/D)-ratio of LCM was 350 (range 25-700) mg/day, 19.7 (range 8.1-56.2) µmol/L, and 0.06 (0.02-0.82) µmol/L/mg, respectively. Serum concentrations were reduced by 28% by concomitant use of enzyme inducers and increased by 30% in patients aged >65 years. Efficacy and tolerability were assessed in 227 patients: 29% had >50% seizure reduction (eight seizure free), 30% had no effect, and 44% reported adverse effects. In Norway, there were on average 500 patients per year using LCM in this period based on NorPD. The study demonstrated pharmacokinetic variability and use of TDM of LCM in Norway. Data were collected from multiple sources for improved pharmacovigilance. Serum concentrations were influenced by enzyme inducers and ageing, indicating the usefulness of TDM. Effect and tolerability were favorable within a suggested reference range of 10-40 µmol/L given drug-fasting conditions.

Role of P-glycoprotein inhibitors in children with drug-resistant epilepsy.

OBJECTIVE: The role of P-glycoprotein (Pgp), one of the known multidrug transporters, has been suggested in drug-resistant epilepsy (DRE). The following study aimed to measure the serum level of Pgp as a possible indicator of tissue Pgp overexpression in patients with DRE and to assess the efficacy of verapamil (as a Pgp inhibitor agent) in these patients. MATERIAL AND METHODS: A group of 24 patients with DRE were recruited and subdivided into two groups, one receiving verapamil and the other receiving a placebo in a double-blind randomized study. Pgp serum levels were measured at enrollment and 12 months later. Twenty medically controlled epileptic patients served as a control group. RESULTS: A significant statistical increase was found in the Pgp level of patients when compared the control group. Patients on both verapamil and the placebo showed improvement in seizure frequency and severity where statistical analysis showed no significant differences. CONCLUSION: Pgp serum levels in patients with DRE were significantly elevated compared to patients with medically controlled epilepsy. The effect of verapamil as Pgp inhibitor on DRE requires further evaluation and research.

Correlating blood and urinary concentrations of clobazam doses in Japanese children and adolescents with intractable epilepsy.

Clobazam (CLB) is an antiepileptic drug that is metabolized to the major metabolite N-desmethylclobazam (N-CLB). Our aim was to evaluate the utility of corrected urinary concentrations of CLB and N-CLB in Japanese children and adolescents with epilepsy. Blood and urinary concentrations of CLB and N-CLB were evaluated in 42 patients. The urinary and peak blood concentrations were measured 2-3 h after the last dose. The ratio of the blood and urinary creatinine concentrations was used to calculate the corrected urinary concentrations. A moderate correlation was found between the CLB dose and the CLB serum concentration, but this correlation was not found for N-CLB. Patients were dichotomized based on two regression lines, which were detected by statistical analyses with a cumulative distribution function: the lower ratio group (CLB/N-CLB < 0.275) and the higher ratio group (≥0.275). Moderate correlations were observed between the CLB dose and the serum concentration or the corrected value of CLB for the lower ratio group, and moderate to strong correlations were observed for the higher ratio group. The corrected urinary concentration of CLB correlates to the CLB dose when stratified by the CLB/N-CLB ratio and may prove practical for clinical estimation of the CLB serum concentration.

Efficacy of the classic ketogenic and the modified Atkins diets in refractory childhood epilepsy.

OBJECTIVE: We aimed to compare the efficacy, safety, and tolerability of a modified Atkins diet (MAD) with the classic ketogenic diet (KD) for the treatment of intractable childhood epilepsy. METHODS: From March 2011 to March 2014, 104 patients aged 1-18 years who had refractory epilepsy were randomly assigned to each diet group (ClinicalTrials.gov, number NCT2100501). A seizure diary record was used to compare seizure frequencies with the baseline prediet seizure frequency at the third and sixth months after diet therapy initiation. RESULTS: Fifty-one patients were assigned to the KD and 53 patients to the MAD. The KD group had a lower mean percentage of baseline seizures compared with the MAD group at 3 months (38.6% for KD, 47.9% for MAD) and 6 months (33.8% for KD, 44.6% for MAD), but the differences were not statistically significant (95% confidence interval [CI] 24.1-50.8, p = 0.291 for 3 months; 95% CI 17.8-46.1, p = 0.255 for 6 months). Instead, for patients aged 1-2 years, seizure outcomes were consistently much more favorable in patients consuming the KD compared with those consuming the MAD. The rate of seizure freedom at 3 months after diet therapy initiation was significantly higher (53% for KD, 20% for MAD, p = 0.047) in these patients. The MAD had advantages with respect to better tolerability and fewer serious side effects. SIGNIFICANCE: The MAD might be considered as the primary choice for the treatment of intractable epilepsy in children, but the classic KD is more suitable as the first line of diet therapy in patients <2 years of age.

Fibronectin is a potential cerebrospinal fluid and serum epilepsy biomarker.

PURPOSE: Previous studies have demonstrated that fibronectin (FN) levels are increased in brain tissues from patients and animals with epilepsy. This study aimed to assess FN levels in cerebrospinal fluid (CSF) and serum samples from patients with epilepsy. METHODS: Fibronectin levels were assessed in CSF and serum samples from 56 patients with epilepsy (27 and 29 individuals with intractable epilepsy and nonintractable epilepsy, respectively) and 25 healthy controls, using sandwich enzyme-linked immunosorbent assays (ELISA). RESULTS: CSF-FN levels were higher in patients with epilepsy (8.07 ± 1.51 mg/l versus 6.20 ± 1.18 mg/l, p<0.05) than in the control group. In addition, serum-FN levels in the group with epilepsy and in the control group were 236.96 ± 65.7 mg/l and 181.43 ± 72.82 mg/l, respectively, indicating a statistically significant difference (p=0.01). Interestingly, serum- and CSF-FN levels in individuals with epilepsy were not affected by antiepileptic drug and duration of epilepsy. Of note, the increase of CSF- and serum-FN levels was more pronounced in subjects with intractable epilepsy than in patients with nonintractable epilepsy. CONCLUSION: Serum- and CSF-FN levels constitute a potential clinical diagnostic biomarker for epilepsy and could also be used for differential diagnosis.