Citations

Abstract Objective To assess the efficacy and safety of fenfluramine in patients with Dravet syndrome (DS) stratified by age, number of previously attempted antiseizure medications (ASMs), and SCN1A pathogenic variant status. Methods In this post hoc analysis, data from three randomized controlled trials (RCTs) in patients with DS (2–18 years) were pooled and stratified by age (<4; ≥4 years), number of previous ASMs (1–3; 4–6; ≥7), and SCN1A pathogenic variant status ( SCN1A +; SCN1A −). Stratified groups were assessed and compared with the pooled placebo group (change in monthly convulsive seizure frequency [MCSF], longest convulsive seizure‐free interval, and Clinical Global Impression–Improvement [CGI–I] scale scores rated by parents/caregivers and investigators), and safety (treatment‐emergent adverse events [TEAEs]: frequency, days to onset, and proportion resolved). Results Among 348 patients included in the RCTs, 216 were randomized to fenfluramine (0.7 mg/kg/day, n = 88; 0.4 mg/kg/day [with stiripentol], n = 43; 0.2 mg/kg/day, n = 85) and 132 to placebo. Compared with placebo, fenfluramine treatment (all doses combined) resulted in greater MCSF reductions, greater increases in longest convulsive seizure‐free intervals, and a higher proportion of parents/caregivers and investigators reporting clinically meaningful improvement (“Much Improved”, “Very Much Improved”) on CGI–I scores across all stratified groups. CGI–I scores were consistent across fenfluramine doses in most stratified groups, but patients with the fewest number of previous ASMs had the greatest frequency of clinically meaningful improvement on investigator‐rated CGI–I scores. Safety outcomes were similar across all strata. Most TEAEs resolved by end‐of‐study. Significance Fenfluramine treatment was associated with improved seizure outcomes and global functioning compared with placebo regardless of age, number of previous ASMs, and SCN1A status in patients with DS. Fenfluramine was well‐tolerated; no new safety signals were identified. Further studies with larger sample sizes (including adults) and a priori inferential analyses of stratified groups are warranted. Plain Language Summary Patients with Dravet syndrome struggle with seizures and everyday life. In three studies, patients aged 2–18 years received fenfluramine or placebo (sugar pill). Fenfluramine lowered seizures without many side effects. Researchers combined results from these studies to see how fenfluramine worked in different patient groups based on age, number of previous medications, and a gene called SCN1A . They looked at seizure reduction and whether doctors felt patients had improved. In all groups, fenfluramine worked better than placebo, with similar side effects. Researchers believe fenfluramine helped these patients, but some groups were small, so these results need to be confirmed.

ABSTRACT Objectives Dravet syndrome (DS) is a severe, drug‐resistant developmental and epileptic encephalopathy (DEE) that requires polytherapy for adequate seizure control. The need to combine multiple antiseizure medications (ASMs), together with variability in seizure types, safety considerations, and evolving patient needs, makes treatment optimization particularly complex for clinicians. As the United States (US) has one of the largest populations of DS patients and pediatric neurologists/epileptologists worldwide, this study aimed to develop US‐focused consensus guidance to guide clinicians in managing treatment combinations in DS. Methods A modified Delphi consensus methodology was applied. 35 statements tailored to the US clinical context were developed, covering six key themes: general treatment principles; strategies to support and empower caregivers; stiripentol (STP) as an add‐on to DS‐specific and nonspecific ASMs; use of fenfluramine (FFA) in STP‐containing regimens; use of cannabidiol (CBD) in STP‐containing regimens; and patient follow‐up during treatment initiation. Statements were submitted for online voting to 52 US clinicians with expertise in DS and experience with all approved DS‐specific ASMs. Agreement was rated using a 9‐point Likert scale, with predefined criteria used to determine strong, good, or absent consensus. Results 26 experts participated in the voting process. Of the 35 statements evaluated, 23 (66%) reached strong consensus, 6 (17%) reached good consensus, and 6 (17%) did not reach consensus. Strong agreement was observed for general principles of DS management, caregiver involvement, structured follow‐up, and several practical aspects of initiating and managing STP‐ and FFA‐containing regimens. Areas without consensus primarily concerned CBD efficacy expectations, dosing strategies, and pharmacokinetic interactions in complex polytherapy regimens. Significance This US‐focused consensus provides structured guidance to support clinical decision‐making in the management of polytherapy for DS. Plain language summary Dravet syndrome is a rare and severe form of epilepsy that begins in early childhood and causes seizures that are difficult to control and often persist throughout life. Because most patients require treatment with multiple medications, managing Dravet syndrome is complex and must adapt as patients grow and their needs change. This US‐focused consensus brings together published evidence and expert clinical experience to provide practical guidance on the management of polytherapy in Dravet syndrome, supporting clinicians in optimizing patient care.

Abstract Objectives Dravet syndrome (DS) is a drug‐resistant developmental and epileptic encephalopathy, often requiring three or more antiseizure medications (ASMs). Consequently, the therapeutic landscape is highly complex, combining DS‐specific agents (stiripentol, STP; cannabidiol, CBD; fenfluramine, FFA), non‐specific ASMs, and non‐pharmacologic options such as dietary therapy or neuromodulation. In addition, recognition of patients' changing needs across the lifespan, together with the essential contribution of caregiver education to effective treatment oversight—including awareness of potential drug–drug interactions and adverse events—emphasizes the value of an integrated and forward‐looking approach. A consensus initiative was developed to guide clinicians in the management of patients with DS, with a particular focus on STP‐containing regimens. Methods Based on a literature review and clinical vignette discussions, a nominal group of five international DS experts developed 38 statements across six themes: (i) general principles, (ii) guiding physicians to empower families, (iii) STP as add‐on to specific and non‐specific Dravet ASMs, (iv) FFA in regimens containing STP, (v) CBD in regimens containing STP, and (vi) patient follow‐up during treatment initiation. Statements were scored on a 9‐point Likert scale (1 = strongly disagree, 9 = strongly agree) first by the nominal group and then by an international panel of 59 DS clinicians. Consensus was defined as ≥75% rating ≥7 and/or a median ≥8. Results Thirty‐four of the 38 statements (89%) reached consensus among both the nominal group and the international panel; one did not reach consensus in either, and three reached consensus only among the nominal group. Both panels agreed on the importance of involving families in treatment decisions and follow‐up, as well as on key aspects of polytherapy management, including ASM initiation, treatment adjustments, and adverse event management. Significance This international consensus integrates evidence and clinical expertise to establish shared principles that address a long‐standing gap in the polytherapeutic management of Dravet syndrome. Plain Language Summary Dravet syndrome is a rare and severe form of epilepsy that begins in early childhood, with seizures that often persist throughout life. Because the disease is highly drug resistant, most patients are treated with polytherapy, making clinical management complex for clinicians. This consensus brings together published evidence and expert experience to provide practical guidance on the management of polytherapy in Dravet syndrome, supporting clinicians in optimizing patient care.

Abstract Objective Dravet syndrome (DS) is the prototypic developmental and epileptic encephalopathy, characterized by drug‐resistant seizures, developmental slowing, and many other morbidities. Detailed characterization of behavioral phenotypes and social–emotional skill development are limited. Methods We prospectively assessed behavioral and social–emotional problems in the ENVISION natural history study (NCT04537832) of children with DS associated with SCN1A pathogenic variants ( SCN1A + DS) enrolled at <5 years of age. Assessments every 3 months for up to 2 years included the Child Behavior Checklist (CBCL), Strengths and Difficulties Questionnaire (SDQ), Brief Infant‐Toddler Social and Emotional Assessment (BITSEA), and Vineland Adaptive Behavior Scales, 3rd Edition (VABS‐3). Results Fifty‐eight children with DS enrolled at 16 sites worldwide. Problematic behaviors—inattention, aggressive or oppositional behaviors, and withdrawn and autistic behaviors—began before age 3 years, became more evident with age, and were clinically significant in many children by age 3–4 years. CBCL Total, Externalizing, and Internalizing Problems T‐scores rose by approximately 3 points per year, and BITSEA Problem scale scores increased by 2.3 points annually ( p = .002). SDQ Hyperactivity scores worsened over time ( p = .013), whereas emotional difficulties remained stable. VABS‐3 Socialization domain scores, which were already more than 1 SD below the normative mean at baseline, decreased further, particularly in younger participants. Correlation analyses showed that poorer communication abilities were associated with increased problematic behaviors ( R = −.55 for CBCL Total Problems and VABS‐3 Communication scores). Mixed‐effects modeling identified age as the strongest predictor of worsening behavioral outcomes. Significance We found that behavioral and social–emotional problems are inherent components of DS that present in toddlerhood and worsen throughout early childhood. This highlights the need to diagnose and manage these issues early. Targeted therapy may alleviate the wide‐ranging morbidities that are intrinsic to DS, including the social–emotional and behavior problems that frequently emerge.

Abstract Objective Dravet syndrome (DS) is a severe developmental and epileptic encephalopathy with a high seizure burden and mortality risk. Stiripentol, one of the first DS‐specific therapies, received FDA approval in 2018 but its real‐world use and impact post‐approval in the USA remain insufficiently characterized. The STIRUS study aimed to assess treatment patterns, clinical efficacy, and quality of life outcomes associated with stiripentol in a contemporary US cohort. Methods STIRUS was a retrospective, multicenter chart review of 98 DS patients who initiated stiripentol after FDA approval and were treated for at least 3 months. Data were collected from 10 USA epilepsy centers on seizure types and frequency, status epilepticus (SE), rescue medication use, emergency room visits, and quality of life, at baseline and during the first and final 3 months on stiripentol. Changes over time were assessed using generalized estimating equation models. Results Initiation of stiripentol was associated with a significant reduction in bilateral convulsive seizure frequency (OR = 2.16, p < 0.006) and a nearly 50% decrease in SE episodes (OR = 2.9, p < 0.003). Importantly, there was a marked decline in rescue medication use and seizure‐related hospital visits: the proportion of patients requiring no rescue medications increased from 23% to over 53%, and those needing frequent emergency interventions dropped from 39% at baseline to 14% during the final 3 months. Quality of life improved in more than half of patients and caregivers. Significance The STIRUS study supports the real‐world efficacy of stiripentol in reducing seizure burden and healthcare utilization in DS. Despite its demonstrated benefits and approval for use in infants, stiripentol remains underutilized and often introduced late in the treatment course. Early and broader adoption may help improve clinical outcomes and quality of life in this vulnerable population. Plain Language Summary The STIRUS study found that stiripentol, an anti‐seizure medication specifically approved for Dravet Syndrome, helped reduce seizures and hospital visits for children living with this severe form of epilepsy. Patients had fewer convulsive seizures, needed fewer rescue medicines, and reported better quality of life. Despite these benefits, stiripentol is still not widely used and often started too late in treatment, suggesting earlier use could further improve outcomes.

Abstract Objective Dravet syndrome (DS) is a developmental and epileptic encephalopathy characterized by drug‐resistant seizures and developmental slowing. Although cognitive and executive function deficits have been described, their early trajectory is not well understood. Methods The prospective ENVISION natural history study (NCT04537832) assessed cognitive, executive, and adaptive function in children younger than 5 years of age with SCN1A + DS every 6 months for up to 2 years using Bayley Scales of Infant and Toddler Development, 3rd Edition (BSID‐III), Wechsler Preschool & Primary Scale of Intelligence, 4th Edition (WPPSI‐IV), Vineland Adaptive Behavior Scales, 3rd Edition (VABS‐3), Behavior Rating Inventory of Executive Function – Preschool Version (BRIEF‐P), and Pediatric Evaluation of Disability Inventory (PEDI). Results Fifty‐eight children were enrolled, with 47% younger than age 2 years. At least 80% of children did not achieve age‐appropriate milestones. Mean BSID‐III Cognitive raw scores increased minimally, with age‐equivalent gains of only 3 months over 1.5 years. Mean Cognitive Composite scores declined significantly by Month 12 (from 81.6 to 72.2; change: –11.0, 95% confidence interval [CI]: −15.3 to −6.8), signaling a widening gap compared with neurotypical development. Executive function worsened, with mean BRIEF‐P Global Executive Composite T‐scores increasing by 3.2 points/year. For some participants, scores were 5 standard deviations (SD) above the normative mean, reflecting abilities profoundly below age expectations (bottom .00003% of the population). Adaptive functioning worsened, with mean VABS‐3 Adaptive Behavior Composite decreasing from 78.7 to 68.1 over 1.5 years (change: –9.0, 95% CI: −11.9 to −6.1) and greater decline among children <2 years at enrollment, with scores decreasing by ~15 points (1 SD). Over half of children >3 years could not remove clothing independently; and when placed on a toilet, 48% could not use it. Significance Infants and young children with SCN1A + DS show significant and progressive developmental slowing across several domains, highlighting urgent need for therapies to mitigate the devastating impact on individuals and families.