Treatment of Lennox-Gastaut syndrome: overview and recent findings

Refining management strategies for Lennox-Gastaut syndrome: Updated algorithms and practical approaches

Lennox-Gastaut syndrome (LGS) is a severe developmental and epileptic encephalopathy (DEE) characterized by multiple types of drug-resistant seizures (which must include tonic seizures) with classical onset before 8 years (although some cases with later onset have also been described), abnormal electroencephalographic features, and cognitive and behavioral impairments. Management and treatment of LGS are challenging, due to associated comorbidities and the treatment resistance of seizures. A panel of five epileptologists reconvened to provide updated guidance and treatment algorithms for LGS, incorporating recent advancements in antiseizure medications (ASMs) and understanding of DEEs. The resulting consensus document is based on current evidence from clinical trials and clinical practice and the panel's expert opinion, focusing on new ASMs with novel mechanisms of action, such as highly purified cannabidiol and fenfluramine. For a patient presenting with newly diagnosed LGS or suspected LGS, the recommended first-line treatment continues to be valproate. If this is ineffective as monotherapy, adjunctive therapy with, firstly, lamotrigine and secondly, rufinamide, is recommended. If seizure control remains suboptimal, subsequent adjunctive ASM treatment options include (alphabetically) cannabidiol, clobazam, felbamate, fenfluramine, and topiramate, although evidence for these is more limited. Whenever possible, no more than two ASMs should be used together. Nonpharmacological treatment approaches should be used in conjunction with ASM therapy and include ketogenic diet therapies, vagus nerve stimulation, and corpus callosotomy. Patients with LGS that has evolved from another type of epilepsy who are not already being treated with valproate should be transitioned to valproate and then managed using the same algorithm as for newly diagnosed LGS. Older patients with established LGS should be reviewed at least annually by a suitably experienced neurologist. The revised guidance aims to improve seizure control and quality of life for patients with LGS through personalized, evidence-based treatment strategies while addressing the challenges of accurate diagnosis and management in a rapidly evolving therapeutic landscape. PLAIN LANGUAGE SUMMARY: Lennox-Gastaut syndrome (LGS) is a severe type of epilepsy that usually starts in childhood but continues into adulthood. It is characterized by a variety of different types of seizures (abnormal electrical activity in the brain), which are difficult to treat and often cause people with the condition to fall and injure themselves. Most people with LGS have learning difficulties and need a lot of support, often in residential care. The authors are experts in treating people with LGS and this article provides up-to-date guidance and advice on how best to care for those with the condition.

A systematic review of electroencephalographic findings in Lennox-Gastaut syndrome

Lennox-Gastaut syndrome (LGS) is a severe form of childhood onset epileptic encephalopathy characterized by multiple drug-resistant seizures, cognitive impairment, and diffuse slow spike and wave (SSW), and generalized paroxysmal fast activity (GPFA) on electroencephalogram (EEG). Systematic review following the Preferred Reporting Items for Systematic Reviews and Meta Analysis (PRISMA) guidelines was done to investigate EEG findings in LGS. PubMed and MEDLINE were systematically searched for English-language studies published until15th may 2023. Original articles and research with patients between age group 1-30 years, and studies with description of EEG findings were included. Search identified 20 studies with 1167 patients. In this analysis 62.6 % of patients were male. The median age was 9.6 years. Etiology was structural abnormality in 42.6 %, genetic in 8.7 % but was unknown in 48.7%. Tonic seizures (74.5 %) were most frequent followed by atypical absences (44.3 %), myoclonic (39.2 %), generalized (38.5 %), atonic (34.8 %), epileptic spasm (15.9 %), focal (11.4 %) and non-convulsive status epilepticus (7.0 %). Out of 20 studies, only 15 studies mentioned GPFA in 46.6 % patients and SSW in 91.7 % patients. Unilateral and focal discharges were more common in patients with unilateral structural abnormalities. Seizure discharges on EEG longer than 10 second duration correlated with seizure diary counts. Combination of atonic, tonic, and atypical absence seizures correlated with SSW, and myoclonic seizures correlated with GPFA. EEG helps in diagnosis and prognosis of LGS. SSW is present in almost all EEG, and GPFA in 46.6 % patients. Longer duration of SSW discharges and disorganized background are associated with poor outcome.

Real-world use of the updated refractory epilepsy screening tool for Lennox-Gastaut syndrome

OBJECTIVE

To evaluate the Refractory Epilepsy Screening Tool for Lennox-Gastaut Syndrome (REST-LGS) for real-world identification of LGS in adults and to develop a scoring system for the tool.

METHODS

A retrospective chart review of adults with drug resistant epilepsy (DRE) and intellectual development disorder (IDD) was conducted by 2 primary care providers blinded to diagnosis. The REST-LGS was designed via the Modified Delphi Consensus and was previously validated. This tool consists of 8 criteria (4 major, 4 minor) considered indicative of LGS. To account for missing data in the earlier validation study and to evaluate applicability in a real-world setting, the REST-LGS was refined to include a scoring system in which major criteria were more heavily weighted than minor criteria, producing categories of "likely" (>11 points), "possible" (8-11 points), and "unlikely" (<8 points) LGS. Statistical analyses were descriptive.

RESULTS

Of the 100 patients included in the analysis, data for slow spike-waves in electroencephalography and seizure onset age - both major REST-LGS criteria - were missing for 46% and 42% of patients, respectively. The majority of patients met 4 of the 8 REST-LGS criteria (cognitive impairment since childhood, 71%; persistent seizures despite a trial of ≥2 antiseizure medications, 65%; seizure onset before the age of 12 years, 57%; ≥2 seizure types, 56%). All 4 major criteria were met in 22 patients (22%). The percentages of patients considered "likely," "possible," or "unlikely" to have LGS were 26%, 30%, and 44%, respectively. Of the 74 patients without a previous LGS diagnosis, 42 (57%) were identified as "possible" or "likely" to have LGS using REST-LGS.

SIGNIFICANCE

In this analysis, the validated REST-LGS was evaluated in a real-world setting. The majority of previously undiagnosed patients were identified via REST-LGS as "possible" or "likely" to have LGS. Extensive missing data highlights challenges of LGS diagnosis in adults.

PLAIN LANGUAGE SUMMARY

There is a need to identify adult patients with Lennox-Gastaut syndrome (LGS) so they can receive appropriate treatment. The Refractory Epilepsy Screening Tool for LGS (REST-LGS) questionnaire was designed by experts to identify whether patients with seizures that are not controlled by medications may have LGS. In this study, 2 physicians completed the REST-LGS using charts for 100 patients who experience seizures not controlled by medications. Of the patients who were previously diagnosed as not having LGS, the majority were "likely" or "possible" to have LGS based on the REST-LGS; therefore, the REST-LGS can identify patients for further evaluation.

A Complex Presentation: Psychosis in a Patient Diagnosed With Lennox-Gastaut Syndrome

Lennox-Gastaut syndrome (LGS) is a form of severe childhood epilepsy, with most children experiencing seizures before reaching the age of eight. Typically, patients have multiple types of seizures, making an accurate diagnosis challenging. While it can be secondary to other causes, often, it is idiopathic. Over time, children develop cognitive impairment, leading to intellectual disability. The mainstay of treatment and management is seizure control. However, management remains challenging due to the complexity of the syndrome, as it is associated with multiple seizure types, intellectual deterioration, and other psychiatric comorbidities. We present the case of a 19-year-old male diagnosed with LGS and treated with various available therapies, who demonstrated multiple breakthrough seizures, significant neurocognitive disabilities, and behavior challenges. Additionally, the patient displayed psychotic features of auditory hallucinations, aggression, and attempts at self-mutilation, a rare clinical presentation in LGS.

Optimal dose of fenfluramine in adjuvant treatment of drug-resistant epilepsy: evidence from randomized controlled trials

Objective

Several clinical trials have suggested that fenfluramine (FFA) is effective for the treatment of epilepsy in Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS). However, the exploration of its optimal target dose is ongoing. This study aimed to summarize the best evidence to inform this clinical issue.

Materials and methods

We searched PubMed, Embase (via Ovid), and Web of Science for relevant literature published before December 1st, 2023. Randomized, double-blind, placebo-controlled studies that evaluated the efficacy, safety, and tolerability of FFA in DS and LGS were identified and meta-analysis was performed according to doses. The study was registered with PROSPERO (CRD42023392454).

Results

Six hundred and twelve patients from four randomized controlled trials were enrolled. The results demonstrated that FFA at 0.2, 0.4, or 0.7 mg/kg/d showed significantly greater efficacy compared to placebo in terms of at least 50% reduction (p < 0.001, p < 0.001, p < 0.001) and at least 75% reduction (p < 0.001, p = 0.007, p < 0.001) in monthly seizure frequency from baseline. Moreover, significantly more patients receiving FFA than placebo were rated as much improved or very much improved in CGI-I by both caregivers/parents and investigators (p < 0.001). The most common treatment-emergent adverse events were decreased appetite, diarrhea, fatigue, and weight loss, with no valvular heart disease or pulmonary hypertension observed in any participant. For dose comparison, 0.7 mg/kg/d group presented higher efficacy on at least 75% reduction in seizure (p = 0.006) but not on at least 50% reduction. Weight loss (p = 0.002), decreased appetite (p = 0.04), and all-cause withdrawal (p = 0.036) were more common in 0.7 mg/kg/d group than 0.2 mg/kg/d. There was no statistical difference in other safety parameters between these two groups.

Conclusion

The higher range of the licensed dose achieves the optimal balance between efficacy, safety, and tolerability in patients with DS and LGS.

Clinical trial registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023392454.

Management of Lennox-Gastaut syndrome with deep brain stimulation: A systematic literature review

OBJECTIVES

To review the current literature regarding the efficacy and safety of deep brain stimulation (DBS) in Lennox-Gastaut syndrome (LGS).

METHODS

The authors conducted a systematic review of PubMed databases using keywords relevant to the objective of this research. Titles and abstracts were reviewed, after which studies that met the inclusion criteria were selected. Findings were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Thirteen studies were identified, and only 3 studies that reported 50 patients (age range from 3 to 65 years) met the inclusion criteria of DBS for LGS. Radiological imaging findings and neurophysiological findings were described in all studies. The thalamus nuclei, particularly the centromedian thalamic nucleus (CMN), were found to be highly active in LGS. By targeting this brain region, patients showed favorable outcomes. Overall, the mean seizure reduction was more than 50% in all patients (among whom 2 were seizure free) at a mean follow-up of 15 (12-18) months.

CONCLUSION

According to this systemic review, DBS for LGS showed satisfactory outcomes, indicating that DBS should be considered a valid treatment option. However, more studies are needed to ensure the role of DBS in LGS by establishing accurate targeting of the CMN using proper lead positioning and radiological imaging, a standard DBS intervention, and long-term outcomes.

Treatment and care of women with epilepsy before, during, and after pregnancy: a practical guide

Women with epilepsy (WWE) wishing for a child represent a highly relevant subgroup of epilepsy patients. The treating epileptologist needs to delineate the epilepsy syndrome and choose the appropriate anti-seizure medication (ASM) considering the main goal of seizure freedom, teratogenic risks, changes in drug metabolism during pregnancy and postpartum, demanding for up-titration during and down-titration after pregnancy. Folic acid or vitamin K supplements and breastfeeding are also discussed in this review. Lamotrigine and levetiracetam have the lowest teratogenic potential. Data on teratogenic risks are also favorable for oxcarbazepine, whereas topiramate tends to have an unfavorable profile. Valproate needs special emphasis. It is most effective in generalized seizures but should be avoided whenever possible due to its teratogenic effects and the negative impact on neuropsychological development of in utero-exposed children. Valproate still has its justification in patients not achieving seizure freedom with other ASMs or if a woman decides to or cannot become pregnant for any reason. When valproate is the most appropriate treatment option, the patient and caregiver must be fully informed of the risks associated with its use during pregnancies. Folate supplementation is recommended to reduce the risk of major congenital malformations. However, there is insufficient information to address the optimal dose and it is unclear whether higher doses offer greater protection. There is currently no general recommendation for a peripartum vitamin K prophylaxis. During pregnancy most ASMs (e.g. lamotrigine, oxcarbazepine, and levetiracetam) need to be increased to compensate for the decline in serum levels; exceptions are valproate and carbamazepine. Postpartum, baseline levels are reached relatively fast, and down-titration is performed empirically. Many ASMs in monotherapy are (moderately) safe for breastfeeding and women should be encouraged to do so. This review provides a practically oriented overview of the complex management of WWE before, during, and after pregnancy.

Truncating mutation in TANC2 in a Chinese boy associated with Lennox-Gastaut syndrome: a case report

Background

Lennox-Gastaut syndrome (LGS) is a severe epileptic encephalopathy that can be caused by brain malformations or genetic mutations. Recently, genome-wide association studies have led to the identification of novel mutations associated with LGS. The TANC2 gene, encodes a synaptic scaffolding protein that interacts with other proteins at the postsynaptic density to regulate dendritic spines and excitatory synapse formation. The TANC2 gene mutations were reported in neurodevelopmental disorders and epilepsy but not in LGS ever.

Case presentation

Here we describe the case of a boy with LGS who presented with multiple seizure patterns, such as myoclonic, atonic, atypical absence, generalized tonic-clonic, focal seizures, and notable cognitive and motor regression. The seizures were refractory to many antiepileptic drugs. He got seizure-free with ketogenic diet combined with antiepileptic drugs. A de novo nonsense mutation c.4321C > T(p.Gln1441Ter) in TANC2 gene was identified by the whole-exome sequencing and confirmed by Sanger sequencing.

Conclusion

We described the first Chinese case with LGS associated to a de novo nonsense mutation c.4321C > T(p.Gln1441Ter) in TANC2 gene, which would expand the clinical spectrum related to TANC2 mutations and contribute to better understanding of genotype-phenotype relationship to guide precision medicine.

Natural Cinnamic Acid Derivatives: A Comprehensive Study on Structural, Anti/Pro-Oxidant, and Environmental Impacts

Cinnamic acid (CA), p-coumaric acid (4-hydroxycinnamic acid, 4-HCA), caffeic acid (3,4-vdihydroxycinnamic acid, 3,4-dHCA), and 3,4,5-trihydroxycinnamic acid (3,4,5-tHCA) were studied for their structural, anti-/pro-oxidant properties and biodegradability. The FT-IR, FT-Raman, UV/Vis, ¹H and ¹³C NMR, and quantum chemical calculations in B3LYP/6-311++G** were performed to study the effect on number and position of hydroxyl group in the ring on the molecular structure of molecules. The antioxidant properties of the derivatives were examined using DPPH^● and HO^● radicals scavenging assays, ferric ion reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), inhibition of linoleic acid oxidation, as well as the biological antioxidant assay with Saccharomyces cerevisiae. Moreover, the pro-oxidant activity of compounds in Trolox oxidation assay was estimated. The effect of the derivatives on environment on the basis of increasing the carbon and nitrogen compounds transformation processes occurring in biological wastewater treatment was studied.

Epidemiology, healthcare resource use, and mortality in patients with probable Lennox-Gastaut syndrome: A population-based study on German health insurance data

OBJECTIVE

This retrospective study examined patients with probable Lennox-Gastaut syndrome (LGS) identified from German healthcare data.

METHODS

This 10-year study (2007-2016) assessed healthcare insurance claims information from the Vilua Healthcare research database. A selection algorithm considering diagnoses and drug prescriptions identified patients with probable LGS. To increase the sensitivity of the identification algorithm, two populations were defined: all patients with probable LGS (broadly defined) and only those with a documented epilepsy diagnosis before 6 years of age (narrowly defined). This specific criterion was used as LGS typically has a peak seizure onset between age 3 and 5 years. Primary analyses were prevalence and demographics; secondary analyses included healthcare costs, hospitalization rate and length of stay (LOS), medication use, and mortality.

RESULTS

In the final year of the study, 545 patients with broadly defined probable LGS (mean [range] age: 31.4 [2-89] years; male: 53%) were identified. Using the narrowly defined probable LGS definition, the number of patients was reduced to 102 (mean [range] age: 7.4 [2-14] years; male: 52%). Prevalence of broadly defined and narrowly defined probable LGS was 39.2 and 6.5 per 100,000 people. During the 10-year study, 208 patients with narrowly defined probable LGS were identified and followed up for 1379 patient-years. The mean annual cost of healthcare was €22,787 per patient-year (PPY); greatest costs were attributable to inpatient care (33%), home nursing care (13%), and medication (10%). Mean annual healthcare costs were significantly greater for those with prescribed rescue medication (45% of patient-years) versus those without (€33,872 vs. €13,785 PPY, p < 0.001). Mean (standard deviation [SD]) annual hospitalization rate was 1.6 (2.0) PPY with mean (SD) annual LOS of 22.7 (46.0) days. Annual hospitalization rate was significantly greater in those who were prescribed rescue medication versus those who were not (2.2 [2.3] vs. 1.1 [1.6] PPY, p < 0.001). The mean (SD) number of different medications prescribed was 11.3 (7.3) PPY and 33.8 (17.0) over the entire observable time per patient (OET); antiepileptic drugs only accounted for 2.1 (1.1) of the medications prescribed PPY and 3.8 (2.0) OET. Over the 10-year study period, mortality in patients with narrowly defined probable LGS was significantly higher than the matched control population (six events [2.88%] vs. oneevent [0.01%], p < 0.001).

CONCLUSION

Annual healthcare costs incurred by patients with probable LGS in Germany were substantial, and mostly attributable to inpatient care, home nursing care, and medication. Patients prescribed with rescue medication incurred significantly greater costs than those who were not. Patients with narrowly defined probable LGS had a higher mortality rate versus control populations.

Expanding the Treatment Landscape for Lennox-Gastaut Syndrome: Current and Future Strategies

Lennox-Gastaut syndrome (LGS), a childhood-onset severe developmental and epileptic encephalopathy (DEE), is an entity that encompasses a heterogenous group of aetiologies, with no single genetic cause. It is characterised by multiple seizure types, an abnormal EEG with generalised slow spike and wave discharges and cognitive impairment, associated with high morbidity and profound effects on the quality of life of patients and their families. Drug-refractory seizures are a hallmark and treatment is further complicated by its multiple morbidities, which evolve over the patient's lifetime. This review provides a comprehensive overview of the current and future options for the treatment of seizures associated with LGS. Six treatments are specifically indicated as adjunct therapies for the treatment of seizures associated with LGS in the US: lamotrigine, clobazam, rufinamide, topiramate, felbamate and most recently cannabidiol. These therapies have demonstrated reductions in drop seizures in 15%-68% of patients across trials, with responder rates (≥ 50% reduction in drop seizures) of 37%-78%. Valproate is still the preferred first-line treatment, generally in combination with lamotrigine or clobazam. Other treatments frequently used off-label include the broad spectrum anti-epileptic drugs (AED) levetiracetam, zonisamide and perampanel, while recent evidence from observational studies has indicated that a newer AED, the levetiracetam analogue brivaracetam, may be effective and well tolerated in LGS patients. Other treatments in clinical development include fenfluramine in late phase III, perampanel, soticlestat-OV953/TAK-953, carisbamate and ganaxolone. Non-pharmacologic interventions include the ketogenic diet, vagus nerve stimulation and surgical interventions; these are also expanding, with the potential for less invasive techniques for corpus callosotomy that have promise for reducing complications. However, despite these advancements, patients continue to experience a significant burden. Because LGS is not a single entity, tailoring of treatment is needed as opposed to a 'one size fits all' approach. Further research is needed into the underlying aetiologies and pathophysiology of LGS, together with advancements in treatments that encompass the spectrum of seizures associated with this complex syndrome.

Clinical implications of trials investigating drug-drug interactions between cannabidiol and enzyme inducers or inhibitors or common antiseizure drugs

Highly purified cannabidiol (CBD) has demonstrated efficacy with an acceptable safety profile in patients with Lennox-Gastaut syndrome or Dravet syndrome in randomized, double-blind, add-on, controlled phase 3 trials. It is important to consider the possibility of drug-drug interactions (DDIs). Here, we review six trials of CBD (Epidiolex/Epidyolex; 100 mg/mL oral solution) in healthy volunteers or patients with epilepsy, which investigated potential interactions between CBD and enzymes involved in drug metabolism of common antiseizure drugs (ASDs). CBD did not affect CYP3A4 activity. Induction of CYP3A4 and CYP2C19 led to small reductions in exposure to CBD and its major metabolites. Inhibition of CYP3A4 activity did not affect CBD exposure and caused small increases in exposure to CBD metabolites. Inhibition of CYP2C19 activity led to a small increase in exposure to CBD and small decreases in exposure to CBD metabolites. One potentially clinically important DDI was identified: combination of CBD and clobazam (CLB) did not affect CBD or CLB exposure, but increased exposure to major metabolites of both compounds. Reduction of CLB dose may be considered if adverse reactions known to occur with CLB are experienced when it is coadministered with CBD. There was a small increase of exposure to stiripentol (STP) when coadministered with CBD. STP had no effect on CBD exposure but led to minor decreases in exposure to CBD metabolites. Combination of CBD and valproate (VPA) did not cause clinically important changes in the pharmacokinetics of either drug, or 2-propyl-4-pentenoic acid. Concomitant VPA caused small increases in exposure to CBD metabolites. Dose adjustments are not likely to be necessary when CBD is combined with STP or VPA. The safety results from these trials were consistent with the known safety profile of CBD. These trials indicate an overall low potential for DDIs between CBD and other ASDs, except for CLB.

Expert opinion: Proposed diagnostic and treatment algorithms for Lennox-Gastaut syndrome in adult patients

Lennox-Gastaut syndrome (LGS) is a severe developmental epileptic encephalopathy diagnosed in childhood that persists through adolescence and into adulthood. While the characteristics of LGS in pediatric patients are well defined, including "drop attacks", interictal slow spike and wave electroencephalogram (EEG) activity, and intellectual disability, these features can evolve over time, and different EEG activities may be present in adult patients with LGS. This may result in missed diagnoses in these patients and subsequent challenges for the adequate treatment of their seizures. Based on discussions held during the LGS Transition of Care advisory board meeting and thereafter, we developed proposed diagnostic and treatment algorithms for LGS in adult patients. We highlight readily available assessments to facilitate diagnosis of LGS, based on past medical history and physical examination. The LGS diagnostic algorithm recommends that clinicians consider the occurrence of wider seizure types and abnormal EEG activities to be potentially indicative of LGS. Seizure types may include atypical absence seizures, myoclonic seizures, focal seizures, and tonic-clonic seizures, and EEG may demonstrate background slowing, focal or multifocal epileptiform discharges, and diffuse fast rhythms during sleep, among other activities. Extended EEG during sleep and video-EEG should be used in equivocal cases. Treatment of LGS in adult patients should incorporate both antiseizure drug (ASD) therapy and nonpharmacologic approaches. Frequent reassessment of patients is considered a central aspect. ASDs were categorized based on order of preference for use in the treatment of LGS; Tier 1 comprises recommended first-line ASDs, and includes valproate, clobazam, lamotrigine, rufinamide, topiramate, and cannabidiol. Other treatment options include diet, neurostimulation, and surgical approaches. Developments with the potential to improve diagnosis in the future include genetic screening, while novel ASDs and advances in neurostimulation techniques may provide valuable treatment options. These algorithms should be frequently revisited to incorporate improved techniques and therapies.

GABAA receptor β3 subunit mutation D120N causes Lennox-Gastaut syndrome in knock-in mice

The Lennox-Gastaut syndrome is a devastating early-onset epileptic encephalopathy, associated with severe behavioural abnormalities. Its pathophysiology, however, is largely unknown. A de novo mutation (c.G358A, p.D120N) in the human GABA type-A receptor β3 subunit gene (GABRB3) has been identified in a patient with Lennox-Gastaut syndrome. To determine whether the mutation causes Lennox-Gastaut syndrome in vivo in mice and to elucidate its mechanistic effects, we generated the heterozygous Gabrb3+/D120N knock-in mouse and found that it had frequent spontaneous atypical absence seizures, as well as less frequent tonic, myoclonic, atonic and generalized tonic-clonic seizures. Each of these seizure types had a unique and characteristic ictal EEG. In addition, knock-in mice displayed abnormal behaviours seen in patients with Lennox-Gastaut syndrome including impaired learning and memory, hyperactivity, impaired social interactions and increased anxiety. This Gabrb3 mutation did not alter GABA type-A receptor trafficking or expression in knock-in mice. However, cortical neurons in thalamocortical slices from knock-in mice had reduced miniature inhibitory post-synaptic current amplitude and prolonged spontaneous thalamocortical oscillations. Thus, the Gabrb3+/D120N knock-in mouse recapitulated human Lennox-Gastaut syndrome seizure types and behavioural abnormalities and was caused by impaired inhibitory GABAergic signalling in the thalamocortical loop. In addition, treatment with antiepileptic drugs and cannabinoids ameliorated atypical absence seizures in knock-in mice. This congenic knock-in mouse demonstrates that a single-point mutation in a single gene can cause development of multiple types of seizures and multiple behavioural abnormalities. The knock-in mouse will be useful for further investigation of the mechanisms of Lennox-Gastaut syndrome development and for the development of new antiepileptic drugs and treatments.

Social cognition and psychopathology in childhood and adolescence

There is a substantial body of research on social cognition in adults with epilepsy, and in broad categories such as focal and generalized epilepsies, but much less has been written about social cognition in children with epilepsy (CWE), and in childhood-onset epilepsy syndromes specifically. In several of these syndromes, autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD), two disorders with social cognitive impairments, are reported. There is strong evidence for social cognitive deficits in juvenile myoclonic epilepsy (JME). There is also a considerable amount of evidence for such deficits in a number of syndromes that may be associated with ASD or ADHD, including West syndrome (WS), Dravet syndrome (DS), and the Landau-Kleffner syndrome (LKS). However, the evidence is of variable quality and incomplete across the range of childhood epilepsy syndromes. In some syndromes, childhood epilepsy substantially increases the risk of severe social cognitive impairment, which may persist after the seizures remit. This paper presents an overview of current research on social cognition in childhood epilepsy, with a particular focus on syndromes with a high prevalence of autistic and behavioral comorbidities. Social cognitive impairments represent a considerable additional challenge for patients and caregivers. Early diagnosis and intervention might significantly improve long-term social cognitive outcomes, highlighting the need for greater awareness among clinicians of this important topic. This article is part of the Special Issue "Epilepsy and social cognition across the lifespan".

A Phase 1, Open-Label, Pharmacokinetic Trial to Investigate Possible Drug-Drug Interactions Between Clobazam, Stiripentol, or Valproate and Cannabidiol in Healthy Subjects

GW Pharmaceuticals' formulation of highly purified cannabidiol oral solution is approved in the United States for seizures associated with Lennox-Gastaut and Dravet syndromes in patients aged ≥2 years, for which clobazam, stiripentol, and valproate are commonly used antiepileptic drugs. This open-label, fixed-sequence, drug-drug interaction, healthy volunteer trial investigated the impact of cannabidiol on steady-state pharmacokinetics of clobazam (and N-desmethylclobazam), stiripentol, and valproate; the reciprocal effect of clobazam, stiripentol, and valproate on cannabidiol and its major metabolites (7-hydroxy-cannabidiol [7-OH-CBD] and 7-carboxy-cannabidiol [7-COOH-CBD]); and cannabidiol safety and tolerability when coadministered with each antiepileptic drug. Concomitant cannabidiol had little effect on clobazam exposure (maximum concentration [Cmax ] and area under the concentration-time curve [AUC], 1.2-fold), N-desmethylclobazam exposure increased (Cmax and AUC, 3.4-fold), stiripentol exposure increased slightly (Cmax , 1.3-fold; AUC, 1.6-fold), while no clinically relevant effect on valproate exposure was observed. Concomitant clobazam with cannabidiol increased 7-OH-CBD exposure (Cmax , 1.7-fold; AUC, 1.5-fold), without notable 7-COOH-CBD or cannabidiol increases. Stiripentol decreased 7-OH-CBD exposure by 29% and 7-COOH-CBD exposure by 13%. There was no effect of valproate on cannabidiol or its metabolites. Cannabidiol was moderately well tolerated, with similar incidences of adverse events reported when coadministered with clobazam, stiripentol, or valproate. There were no deaths, serious adverse events, pregnancies, or other clinically significant safety findings.

Therapeutic approach to Lennox-Gastaut syndrome: a systematic review

Lennox-Gastaut syndrome (LGS) is a rare, age-related syndrome, characterized by multiple seizure types, mental regression, and specific EEG abnormalities. It is one of the most challenging epilepsy: treatment is rarely effective and the final prognosis remains poor, despite the availability of several antiepileptic drugs, validated through well-designed, randomized, controlled trials. However, it is reasonable to consider non-medical treatments, such as surgery, after failure of two-to-three drugs. This review has as goal to describe systematically the different therapeutic options for LGS, including, not only recognized antiepileptic drugs, but also new oral drugs, immune therapy, diet, surgery, and neurostimulation techniques.

An evaluation of clobazam tablets and film (AQST-120) for the treatment of Lennox-Gastaut syndrome

Introduction: Lennox-Gastaut syndrome (LGS) is a chronic, epileptic encephalopathy, characterized by multiple seizure types, distinctive slow spike-wave patterns in the electroencephalogram (EEG), and severe cognitive and behavioral comorbidities. Seizures are typically refractory and long-term prognosis is poor. No antiseizure drug (ASD) is fully effective as a monotherapy. Clobazam (CLB) was licensed in the United States in 2011 as an adjunctive therapy for seizures in LGS. In 2018, a new formulation, CLB oral soluble film (COSF) (AQST-120), was approved by the Federal Drug Administration (FDA) for the same indication. Areas covered: The authors summarize current pharmacological options and guidelines for the management of seizures in LGS and efficacy and safety findings from phase II and III randomized controlled trials of adjunctive CLB in patients with LGS. An open-label extension trial is also considered. A pharmacokinetic comparison of COSF and CLB tablets is also undertaken. Expert opinion: CLB is partly effective as an add-on therapy in treating seizures in LGS. Adverse effects, pharmacokinetic interactions and the potential for tolerance with long-term treatment should be weighed against the clinical benefit when considering the introduction of CLB in this population. COSF has a similar pharmacokinetic profile to CLB tablets and may help to improve adherence to treatment.

Treatment of Seizures Associated with Lennox-Gastaut and Dravet Syndromes: A Focus on Cannabidiol Oral Solution

Cannabidiol oral solution for seizures associated with Lennox-Gastaut and Dravet syndromes.

[Omega-6/omega-3 ratio and cognition in children with epilepsy]

INTRODUCTION

Cognitive impairment is a common consequence of epilepsy in children. This study aimed to assess the ratio of omega-6 to omega-3 fatty acid levels and its impact on cognitive function in children with idiopathic epilepsy.

PATIENTS AND METHODS

We performed a case-control study in 30 children with idiopathic epilepsy and 20 healthy children. We measured levels of alpha-linolenic acid (omega-3) and linoleic acid (omega-6) by means of gas-liquid chromatography. We assessed cognitive function with the Arabic version of the fourth edition of the Stanford-Binet test and the P300 component of event-related potentials. All children had an intelligent quotient greater than 70.

RESULTS

Children with epilepsy had lower levels of omega-3 and higher levels of omega-6 fatty acids and an abnormal omega-6/omega-3 ratio compared to non-epileptic children. We found a significant positive correlation of serum omega-3 levels and a significant negative correlation of serum omega-6 levels with cognitive function scores and P300 latency in children with epilepsy.

CONCLUSION

Children with epilepsy have abnormal ratios of omega-6 to omega-3 fatty acid serum levels, which is associated with impaired cognitive function in these children.

[Why the diagnosis of Lennox-Gastaut syndrome is a rare one?]

The review addresses the problem of the diagnosis of Lennox-Gastaut syndrome, a severe epileptic encephalopathy. Despite the presence of a vivid clinical and encephalographic picture, classical Lennox-Gastaut syndrome, which meets all of its diagnostic criteria, is quite rare. Many authors believe that the diagnosis of the syndrome is possible if the patient has tonic seizures and typical ictal and interictal patterns on the electroencephalogram (EEG). The diagnosis of the syndrome is considered probable if there are typical EEG patterns of wakefulness and sleep, but no tonic seizures are recorded. Diagnosis of the syndrome is complicated by its polyetiology (clinical and EEG manifestations can vary significantly), the evolution of seizure types and EEG characteristics as the patient matures, the presence of other epileptic syndromes similar to Lennox-Gastaut syndrome.

Evaluation of long-term safety, tolerability, and behavioral outcomes with adjunctive rufinamide in pediatric patients (≥1 to <4 years old) with Lennox-Gastaut syndrome: Final results from randomized study 303

OBJECTIVE

Evaluate the long-term safety, tolerability, and behavioral effects of adjunctive rufinamide in pediatric patients (≥1 to <4 years old) with inadequately controlled seizures associated with Lennox-Gastaut syndrome (LGS).

METHODS

Study 303 (ClinicalTrials.gov identifier NCT01405053) was a multicenter, randomized, open-label, Phase III trial. Patients were randomized (2:1) to oral suspension rufinamide (≤45 mg/kg/day) or any other investigator-chosen antiepileptic drug (AED) for a 2-year treatment period. Primary safety/tolerability assessments included monitoring of treatment-emergent adverse events (TEAEs) and serious TEAEs. Behavioral effects were assessed via the Child Behavior Checklist (CBCL) using the Total Problems score and change from baseline in CBCL Total Problems score. CBCL subscores were also evaluated.

RESULTS

The Safety Analysis Set included 37 patients (rufinamide: n = 25; any other AED: n = 12). TEAE incidence was similar between the rufinamide (88.0%) and any-other-AED groups (83.3%); serious TEAE incidence was also similar between treatment groups (40.0% and 41.7%, respectively). Between treatment groups, the difference in the least squares mean CBCL Total Problems score across time was not significant (p = 0.7083), behavior outcomes were similar across all endpoints, and there were no consistent trends in CBCL subscores.

SIGNIFICANCE

Long-term (2 years) adjunctive rufinamide was well tolerated in pediatric patients with LGS. Behavioral outcomes were comparable between the rufinamide and any-other-AED groups, however the small sample size and difficulties assessing behavior in this population should be noted. The challenges of this study raise the issue of revising how studies in very young children with rare and complex epilepsies are performed.

Rufinamide efficacy and safety in children aged 1-4 years with Lennox-Gastaut syndrome

PURPOSE

The treatment options for Lennox-Gastaut syndrome (LGS), a pediatric epileptic syndrome, are limited, especially in younger children. Rufinamide tablets were safe and effective as an add-on treatment in Korean children and adolescents <20 years of age with LGS. This subgroup analysis aimed to evaluate the efficacy and safety of rufinamide tablets in LGS pediatric patients aged 1-4 years.

METHODS

This was a retrospective, observational study in LGS patients aged 1-4 years who received 12 weeks of treatment with rufinamide orally as an adjuvant treatment between April and June 2010. The proportion of responders (patients with a ≥50% reduction in seizure frequency after rufinamide treatment) was evaluated according to the type of seizure. The proportion of patients who were seizure-free was also evaluated. Adverse events (AEs) were evaluated after 12 weeks of treatment.

RESULTS

Among the 15 patients evaluated, one discontinued treatment because of worsening seizures 4 weeks after administration of rufinamide. Seven (46.67%) patients were responders and four patients were seizure-free. There were four responders with convulsive seizures, one each for myoclonic seizures and drop attacks, and spasms. The responder rate was increased to 69.23% by long-term treatment of rufinamide. AEs were experienced by three patients. One patient each experienced somnolence, fatigue, and rash.

CONCLUSION

Rufinamide tablets were efficacious and well tolerated in LGS patients aged 1-4 years, at doses up to 1000 mg per day, when given as add-on therapy to other antiepileptic drugs.

A Comprehensive Overview of the Clinical Pharmacokinetics of Clobazam

Clobazam (CLB) is a 1,5‐benzodiazepine that has been widely used as an anxiolytic and antiseizure drug (ASD) since it was first synthesized over 50 years ago. CLB was approved in the United States in 2011 as adjunctive therapy for seizures in patients ≥2 years old with Lennox‐Gastaut syndrome. CLB pharmacokinetics (PK) have been studied in single‐ and multiple‐dose administrations in healthy subjects. Salient features include high bioavailability, linear PK, and negligible effects from coadministration of other ASDs. CLB is highly and extensively absorbed, with little effect from food; time to maximum plasma concentration is 0.5 to 4 hours following the dose. After CLB doses of 20 to 40 mg/day, the volume of distribution is 99 to 120 L, with oral clearance ranging from 1.9 to 2.3 L/h. CLB is lipophilic and distributes throughout the body after oral administration. It is metabolized in the liver by cytochrome P450 (CYP) isoenzymes CYP3A, CYP2C19, and CYP2B6, and its main active metabolite is N‐desmethylclobazam. The half‐life of CLB after a single oral dose ranges from 36 to 42 hours; the half‐life of N‐desmethylclobazam ranges from 59 to 74 hours. The metabolites of CLB are primarily excreted renally. Population PK modeling using data from healthy subjects and patients with Lennox‐Gastaut syndrome indicates that race, sex, age, weight, and renal function do not influence CLB PK. As CLB has been extensively studied since the 1970s, this review is meant to provide a consolidated and comprehensive resource on CLB PK for both prescribers and scientists alike.

Lennox-Gastaut Syndrome: In a Nutshell

Lennox-Gastaut syndrome is one of the rare childhood-onset epileptic encephalopathies, characterized by multiple type seizure disorder, the typical pattern on electroencephalogram and intellectual disability. Tonic-type seizures are most commonly seen in these patients. Behavioral disturbances and cognitive decline are gradual-onset and last long after the first episode of epileptiform activity. In most cases, there is some identifiable cause that has led to the clinical presentation of the patient. Various pharmacological and surgical procedures have been proposed for the treatment of Lennox-Gastaut syndrome and many more to come in the very near future to overcome the drug resistance and to avoid the patient forming a life-long dependency.

Cannabidiol in patients with seizures associated with Lennox-Gastaut syndrome (GWPCARE4): a randomised, double-blind, placebo-controlled phase 3 trial

BACKGROUND

Patients with Lennox-Gastaut syndrome, a rare, severe form of epileptic encephalopathy, are frequently treatment resistant to available medications. No controlled studies have investigated the use of cannabidiol for patients with seizures associated with Lennox-Gastaut syndrome. We therefore assessed the efficacy and safety of cannabidiol as an add-on anticonvulsant therapy in this population of patients.

METHODS

In this randomised, double-blind, placebo-controlled trial done at 24 clinical sites in the USA, the Netherlands, and Poland, we investigated the efficacy of cannabidiol as add-on therapy for drop seizures in patients with treatment-resistant Lennox-Gastaut syndrome. Eligible patients (aged 2-55 years) had Lennox-Gastaut syndrome, including a history of slow (<3 Hz) spike-and-wave patterns on electroencephalogram, evidence of more than one type of generalised seizure for at least 6 months, at least two drop seizures per week during the 4-week baseline period, and had not responded to treatment with at least two antiepileptic drugs. Patients were randomly assigned (1:1) using an interactive voice response system, stratified by age group, to receive 20 mg/kg oral cannabidiol daily or matched placebo for 14 weeks. All patients, caregivers, investigators, and individuals assessing data were masked to group assignment. The primary endpoint was percentage change from baseline in monthly frequency of drop seizures during the treatment period, analysed in all patients who received at least one dose of study drug and had post-baseline efficacy data. All randomly assigned patients were included in the safety analyses. This study is registered with ClinicalTrials.gov, number NCT02224690.

FINDINGS

Between April 28, 2015, and Oct 15, 2015, we randomly assigned 171 patients to receive cannabidiol (n=86) or placebo (n=85). 14 patients in the cannabidiol group and one in the placebo group discontinued study treatment; all randomly assigned patients received at least one dose of study treatment and had post-baseline efficacy data. The median percentage reduction in monthly drop seizure frequency from baseline was 43·9% (IQR -69·6 to -1·9) in the cannibidiol group and 21·8% (IQR -45·7 to 1·7) in the placebo group. The estimated median difference between the treatment groups was -17·21 (95% CI -30·32 to -4·09; p=0·0135) during the 14-week treatment period. Adverse events occurred in 74 (86%) of 86 patients in the cannabidiol group and 59 (69%) of 85 patients in the placebo group; most were mild or moderate. The most common adverse events were diarrhoea, somnolence, pyrexia, decreased appetite, and vomiting. 12 (14%) patients in the cannabidiol group and one (1%) patient in the placebo group withdrew from the study because of adverse events. One patient (1%) died in the cannabidiol group, but this was considered unrelated to treatment.

INTERPRETATION

Add-on cannabidiol is efficacious for the treatment of patients with drop seizures associated with Lennox-Gastaut syndrome and is generally well tolerated. The long-term efficacy and safety of cannabidiol is currently being assessed in the open-label extension of this trial.

FUNDING

GW Pharmaceuticals.

An Updated Overview on Therapeutic Drug Monitoring of Recent Antiepileptic Drugs

Given the distinctive characteristics of both epilepsy and antiepileptic drugs (AEDs), therapeutic drug monitoring (TDM) can make a significant contribution to the field of epilepsy. The measurement and interpretation of serum drug concentrations can be of benefit in the treatment of uncontrollable seizures and in cases of clinical toxicity; it can aid in the individualization of therapy and in adjusting for variable or nonlinear pharmacokinetics; and can be useful in special populations such as pregnancy. This review examines the potential for TDM of newer AEDs such as eslicarbazepine acetate, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, perampanel, pregabalin, rufinamide, retigabine, stiripentol, tiagabine, topiramate, vigabatrin, and zonisamide. We describe the relationships between serum drug concentration, clinical effect, and adverse drug reactions for each AED as well as the different analytical methods used for serum drug quantification. We discuss retrospective studies and prospective data on the serum drug concentration-efficacy of these drugs and present the pharmacokinetic parameters, oral bioavailability, reference concentration range, and active metabolites of newer AEDs. Limited data are available for recent AEDs, and we discuss the connection between drug concentrations in terms of clinical efficacy and nonresponse. Although we do not propose routine TDM, serum drug measurement can play a beneficial role in patient management and treatment individualization. Standardized studies designed to assess, in particular, concentration-efficacy-toxicity relationships for recent AEDs are urgently required.

Optimizing clobazam treatment in patients with Lennox-Gastaut syndrome

Given the complexities managing Lennox-Gastaut syndrome (LGS)-comorbid conditions, multiple associated seizure types that tend to be refractory to treatment-dosage optimization of antiepileptic drug (AED) treatment is a challenge. In the absence of clinical trial data on optimization of AED dosage in patients with LGS, dose titration is guided by personal experience, anecdotal evidence, and specific patient factors (age, comorbid conditions and medications, seizure types, etc.). The goal of this study was to determine whether a 20% increase in adjunctive clobazam was a reasonable benchmark for improved seizure response in patients with LGS who had responded to adjunctive clobazam treatment during a 12-week lead-in trial. This was a post hoc analysis of data from a long-term, open-label extension (OLE) study, which comprised patients who completed 1 of 2 pivotal clobazam lead-in studies. During the lead-in studies, patients received either placebo or clobazam (0.25, 0.50, or 1.0mg/kg/d) (maximum 40mg/d); during OLE, patients received clobazam up to 2.0mg/kg/d (maximum 80mg/d). The post hoc analysis population comprised patients who had ≥25%, ≥50%, or ≥75% seizure reduction from baseline during lead-in clobazam treatment and ≥12months of follow-up data during OLE. Successful dosage increase (i.e., dosage optimization) was defined as ≥20% clobazam dosage increase from OLE baseline, and improved seizure control from OLE baseline (improvement in seizure responder status, or >50% reduction in total seizure frequency). Patients were stratified by responder status after lead-in treatment (OLE baseline) and by lead-in clobazam dosage received. The findings of the analysis indicated that clobazam dosage increases of ≥20% during long-term treatment improved seizure control >80% of patients with LGS who responded to clobazam during lead-in treatment. Rates of successful dosage increase during OLE were high regardless of lead-in dosage received, with the highest rate of successful dosage increase among patients who received low-dosage clobazam during lead-in. Similarly, rates of successful dose increase were high regardless of lead-in seizure responder category, with the highest rates occurring in patients with the highest (≥75%) lead-in response.

Expert Opinion on the Management of Lennox-Gastaut Syndrome: Treatment Algorithms and Practical Considerations

Lennox–Gastaut syndrome (LGS) is a severe epileptic and developmental encephalopathy that is associated with a high rate of morbidity and mortality. It is characterized by multiple seizure types, abnormal electroencephalographic features, and intellectual disability. Although intellectual disability and associated behavioral problems are characteristic of LGS, they are not necessarily present at its outset and are therefore not part of its diagnostic criteria. LGS is typically treated with a variety of pharmacological and non-pharmacological therapies, often in combination. Management and treatment decisions can be challenging, due to the multiple seizure types and comorbidities associated with the condition. A panel of five epileptologists met to discuss consensus recommendations for LGS management, based on the latest available evidence from literature review and clinical experience. Treatment algorithms were formulated. Current evidence favors the continued use of sodium valproate (VPA) as the first-line treatment for patients with newly diagnosed de novo LGS. If VPA is ineffective alone, evidence supports lamotrigine, or subsequently rufinamide, as adjunctive therapy. If seizure control remains inadequate, the choice of next adjunctive antiepileptic drug (AED) should be discussed with the patient/parent/caregiver/clinical team, as current evidence is limited. Non-pharmacological therapies, including resective surgery, the ketogenic diet, vagus nerve stimulation, and callosotomy, should be considered for use alongside AED therapy from the outset of treatment. For patients with LGS that has evolved from another type of epilepsy who are already being treated with an AED other than VPA, VPA therapy should be considered if not trialed previously. Thereafter, the approach for a de novo patient should be followed. Where possible, no more than two AEDs should be used concomitantly. Patients with established LGS should undergo review by a neurologist specialized in epilepsy on at least an annual basis, including a thorough reassessment of their diagnosis and treatment plan. Clinicians should always be vigilant to the possibility of treatable etiologies and alert to the possibility that a patient’s diagnosis may change, since the seizure types and electroencephalographic features that characterize LGS evolve over time. To date, available treatments are unlikely to lead to seizure remission in the majority of patients and therefore the primary focus of treatment should always be optimization of learning, behavioral management, and overall quality of life.

Use and cost comparison of clobazam to other antiepileptic drugs for treatment of Lennox-Gastaut syndrome

Background: Lennox-Gastaut syndrome (LGS) is a severe form of childhood-onset epilepsy associated with serious injuries due to frequent and severe seizures. Of the antiepileptic drugs (AEDs) approved for LGS, clobazam is a more recent market entrant, having been approved in October 2011. Recent AED budget impact and cost-effectiveness analyses for LGS suggest that adding clobazam to a health plan formulary may result in decreased medical costs; however, research on clinical and economic outcomes and treatment patterns with these AED treatments in LGS is limited. Objectives: To compare the baseline characteristics and treatment patterns of new initiators of clobazam and other AEDs among LGS patients and compare healthcare utilization and costs before and after clobazam initiation among LGS patients. Methods: A retrospective study of probable LGS patients was conducted using the MarketScan® Commercial, Medicare Supplemental, and Medicaid databases (10/1/2010-3/31/2014). Results: In the Commercial/Medicare Supplemental population, clobazam users were younger, had fewer comorbidities, and more prior AED use than non-clobazam users. In the 12 months pre-treatment initiation, clobazam users had significantly more seizure-related inpatient stays and outpatient visits and higher total seizure-related (P < 0.001) and all-cause (P < 0.001) costs than non-clobazam users. Among clobazam users, when compared to the 12 months pre-clobazam initiation, seizure-related medical utilization and costs were lower in the 12 months post-clobazam initiation (P = 0.004). Total all-cause (P < 0.001) and seizure-related (P = 0.029) costs increased post-clobazam initiation mainly due to the increase in outpatient pharmacy costs. Similar results were observed in the Medicaid population. Conclusions: Baseline results suggest a prescribing preference for clobazam in severe LGS patients. Clobazam users had a reduction in seizure-related medical utilization and costs after clobazam initiation. The improvement in medical costs mostly offset the higher prescription costs following clobazam initiation.

Rufinamide in children and adults in routine clinical practice

OBJECTIVE

To explore the long-term effectiveness of rufinamide in managing Lennox-Gastaut Syndrome (LGS), other epileptic encephalopathies, and intractable focal epilepsies in adults and children in routine clinical practice.

METHODS

A multicentre, retrospective chart review of patients prescribed adjunctive rufinamide at seven Spanish epilepsy centres, with assessments at six and 12 months.

RESULTS

We evaluated data from 58 patients (40 male, age range 7-57 years), 25 of whom were diagnosed with LGS, 12 with other epileptic encephalopathies and 21 of whom were diagnosed with focal epilepsies, mainly frontal lobe. The mean daily rufinamide dose was 32.0 mg/kg (range 12.5-66.7 mg/kg) in children and 24.7 mg/kg (range 5.0-47.0 mg/kg) in adults, and the most commonly used concomitant antiepileptic drugs were levetiracetam and valproate. Rufinamide was discontinued in 25 patients (43.1%) during the 1-year follow-up, and the most common reason was lack of effectiveness (n = 12, 20.7% of total). The frequency of generalized tonic-clonic seizures was significantly reduced from baseline at 6 and 12 months (P = 0.001), both in patients with generalized epilepsies and in patients with focal epilepsies. Significant seizure frequency reduction from baseline was observed at 12 months (P = 0.01) for tonic/atonic seizures and at 6 months (P = 0.001) for focal seizures. Side effects were reported in 21 patients (36.2%): nausea, vomiting and weight loss were most frequent.

CONCLUSIONS

Rufinamide was well tolerated and was effective in reducing frequency of generalized tonic-clonic, tonic/atonic and focal seizures in both children and adults with severe refractory epilepsies, primarily LGS.

Safety and pharmacokinetic profile of rufinamide in pediatric patients aged less than 4 years with Lennox-Gastaut syndrome: An interim analysis from a multicenter, randomized, active-controlled, open-label study

OBJECTIVE

A good knowledge of safety and age group-specific pharmacokinetics (PK) of antiepileptic drugs (AEDs) in young pediatric patients is of great importance in clinical practice. This paper presents 6-month interim safety and PK from an ongoing 2-year open-label study (Study 303) of adjunctive rufinamide treatment in pediatric subjects ≥ 1 to < 4 years with inadequately controlled epilepsies of the Lennox-Gastaut syndrome (LGS) spectrum.

METHODS

Subjects (N = 37) were randomized to either rufinamide or any other approved AED chosen by the investigator as adjunctive therapy to the subject's existing regimen of 1-3 AEDs.

RESULTS

Interim safety results showed that treatment-emergent adverse events (TEAEs) were similar between the rufinamide (22 [88.0%]) and any-other-AED group (9 [81.8%]), with most events considered mild or moderate. A population PK analysis was conducted including plasma rufinamide concentrations from Study 303 and two other study populations of LGS subjects ≥ 4 years. The rufinamide PK profile was dose independent. The apparent clearance (CL/F) estimated from the PK model was 2.19 L/h; it was found to increase significantly as a function of body weight. Coadministration of valproic acid significantly decreased rufinamide CL/F. CL/F was not significantly affected by other concomitant AEDs, age, gender, race, hepatic function, or renal function. No adjustments to body weight-based rufinamide dosing in subjects ≥ 1 to < 4 years are necessary.

SIGNIFICANCE

Rufinamide was safe and well tolerated in these pediatric subjects. Results from the interim analysis demonstrate that rufinamide's safety and PK profile is comparable in subjects ≥ 1 to < 4 and ≥ 4 years with LGS.

CLINICAL TRIAL REGISTRATION

Study 303 (clinicaltrials.gov: NCT01405053).

Cannabinoids and Epilepsy

Cannabis has been used for centuries to treat seizures. Recent anecdotal reports, accumulating animal model data, and mechanistic insights have raised interest in cannabis-based antiepileptic therapies. In this study, we review current understanding of the endocannabinoid system, characterize the pro- and anticonvulsive effects of cannabinoids [e.g., Δ9-tetrahydrocannabinol and cannabidiol (CBD)], and highlight scientific evidence from pre-clinical and clinical trials of cannabinoids in epilepsy. These studies suggest that CBD avoids the psychoactive effects of the endocannabinoid system to provide a well-tolerated, promising therapeutic for the treatment of seizures, while whole-plant cannabis can both contribute to and reduce seizures. Finally, we discuss results from a new multicenter, open-label study using CBD in a population with treatment-resistant epilepsy. In all, we seek to evaluate our current understanding of cannabinoids in epilepsy and guide future basic science and clinical studies.

Lennox-Gastaut syndrome. Management update

Lennox-Gastaut syndrome (LGS) is a severe pediatric epilepsy syndrome characterized by mixed seizures, cognitive decline, and generalized slow (<3 Hz) spike wave discharges on electroencephalography. Atonic seizures result in dangerous drop attacks with risks of injury and impairment of the quality of life. The seizures are frequently resistant to multiple antiepileptic (AED) drugs. Newer AEDs, such as rufinamide, are now available. When multiple AED trials fail, non-pharmacological treatments such as the ketogenic diet, vagus nerve stimulation, and epilepsy surgery, should be considered. The aim of this review is to present an updated outline of LGS and the available treatments. Although the prognosis for complete seizure control remains poor, the addition of newer therapies provides an improved hope for some of these patients and their families. Further long term randomized controlled trials are required to compare different therapeutic interventions in terms of efficacy and tolerability.

Conceptualizing lennox-gastaut syndrome as a secondary network epilepsy

Lennox–Gastaut Syndrome (LGS) is a category of severe, disabling epilepsy, characterized by frequent, treatment-resistant seizures, and cognitive impairment. Electroencephalography (EEG) shows characteristic generalized epileptic activity that is similar in those with lesional, genetic, or unknown causes, suggesting a common underlying mechanism. The condition typically begins in young children, leaving many severely disabled with recurring seizures throughout their adult life. Scalp EEG of the tonic seizures of LGS is characterized by a diffuse high-voltage slow transient evolving into generalized low-voltage fast activity, likely reflecting sustained fast neuronal firing over a wide cortical area. The typical interictal discharges (runs of slow spike-and-wave and bursts of generalized paroxysmal fast activity) also have a “generalized” electrical field, suggesting widespread cortical involvement. Recent brain mapping studies have begun to reveal which cortical and subcortical regions are active during these “generalized” discharges. In this critical review, we examine findings from neuroimaging studies of LGS and place these in the context of the electrical and clinical features of the syndrome. We suggest that LGS can be conceptualized as “secondary network epilepsy,” where the epileptic activity is expressed through large-scale brain networks, particularly the attention and default-mode networks. Cortical lesions, when present, appear to chronically interact with these networks to produce network instability rather than triggering each individual epileptic discharge. LGS can be considered as “secondary” network epilepsy because the epileptic manifestations of the disorder reflect the networks being driven, rather than the specific initiating process. In this review, we begin with a summation of the clinical manifestations of LGS and what this has revealed about the underlying etiology of the condition. We then undertake a systematic review of the functional neuroimaging literature in LGS, which leads us to conclude that LGS can best be conceptualized as “secondary network epilepsy.”

Lacosamide in Lennox-Gastaut syndrome: case report

INTRODUCTION

Lennox Gastaut syndrome (LGS) is an epileptic encephalopathy characterized by tonic, atonic, and atypical absence seizures usually refractory to pharmacological treatment. Patients generally continue with seizures despite treatment with the commercially available antiepileptic drugs (AEDs). Lacosamide (LCM) is a new AED recently approved for treatment of partial onset seizures with or without secondary generalization. Lacosamide has a novel mechanism of action that seems to be different in relation to other conventional AEDs.

OBJECTIVE

To report LCM-caused worsening of tonic seizures and electroencephalographic pattern in a patient with Lennox-Gastaut syndrome.

CASE REPORT

We report the evolution of a patient with LGS resistant to several AEDs with a cryptogenic hepatopathy in whom LCM caused worsening of tonic seizures and electroencephalographic pattern. Once LCM was discontinued, the patient returned to his clinical and electrical baseline.

CONCLUSION

Lennox Gastaut syndrome may exacerbate tonic seizures and electrical pattern of patients with LGS.

lennox-Gastaut syndrome: an updateon treatment

Lennox-Gastaut syndrome (LGS) is a severe epileptic encephalopathy. Few current treatment options are effective in improving seizure control. This paper reviews the available treatments of LGS and discusses a new option in Canada, rufinamide. It is a wide spectrum anticonvulsant, approved in a number of countries for the treatment of LGS. In a randomized controlled trial in the LGS population, adjunctive rufinamide therapy has been shown to offer significantly greater reduction in total seizure frequency and tonic-atonic seizure frequency in comparison to placebo. Efficacy has been assessed over three years and appears to be sustained. Most adverse events were cognitive (e.g. somnolence) or gastrointestinal in nature and in many cases transient or mild. based on the efficacy and safety data on rufinamide obtained to date, this medication will provide additional benefits to patients with LGS in Canada and is an important consideration for our patients in the adjunctive treatment setting.

Epileptic encephalopathies: an overview

Epileptic encephalopathies are an epileptic condition characterized by epileptiform abnormalities associated with progressive cerebral dysfunction. In the classification of the International League Against Epilepsy eight age-related epileptic encephalopathy syndromes are recognized. These syndromes include early myoclonic encephalopathy and Ohtahara syndrome in the neonatal period, West syndrome and Dravet syndrome in infancy, myoclonic status in nonprogressive encephalopathies, and Lennox-Gastaut syndrome, Landau-Kleffner syndrome, and epilepsy with continuous spike waves during slow wave sleep in childhood and adolescences. Other epileptic syndromes such as migrating partial seizures in infancy and severe epilepsy with multiple independent spike foci may be reasonably added. In this paper, we provide an overview of epileptic encephalopathies including clinical neurophysiological features, cognitive deterioration, and management options especially that these conditions are generally refractory to standard antiepileptic drugs.