Patient-advocate-led global coalition adapting fit-for-purpose outcomes measures to assure meaningful inclusion of DEEs in clinical trials.

Existing clinical tools that measure non-seizure outcomes lack the range and granularity needed to capture skills in developmental and epileptic encephalopathy (DEE)-affected individuals who also fall in the severe to profound range of intellectual disability. This effectively excludes those with severe impairments from clinical trials, impeding the ability of sponsors to evaluate disease-modifying therapies (DMTs). The Inchstone Project, an international, patient advocate-led collaboration, brings together leading researchers, clinicians, pharmaceutical companies, and advocates to develop an adapted, validated assessment battery within 5 years. The goal is to support trials of DMTs for the DEEs by providing sufficiently sensitive measurement tools to demonstrate therapeutic efficacy. An initial pilot study administered 7 established assessments to 10 individuals affected by SCN2A-DEE, identifying specific limitations of existing measures and areas for improvement. It was clear that most tools do not account for challenges throughout the DEE population, including vision impairments, significant motor impairments and profound intellectual disability, which need to be accounted for in creating a 'fit-for-purpose' battery for the DEE population. Several novel assessments, including two measures of responsivity developed for use in monitoring recovery after acquired brain injury as well as individualized Goal Attainment Scaling, showed promise in this group. The team also completed a DEE-wide survey with over 270 caregivers documenting their children's abilities and priorities for their improvement from new treatments. The Inchstone team is using this information to evaluate how existing tools might be updated to better capture what is most important to families and measure their child's small but important improvements over time. These efforts are building a coherent picture across multiple DEEs of what domains, or concepts of interest, have the greatest impact on most patients and families. The Inchstone team is on course to adapt non-seizure outcome measures that are (1) sufficiently sensitive to measure small increments of meaningful change ('Inchstones') and (2) applicable to multiple DEE conditions.

DEE-P Connection's Inchstone project is adapting assessment tools to measure the smallest developmental changes in those affected by developmental and epileptic encephalopathies (DEEs) - severe epilepsy and related developmental disorders. More sensitive measures will allow profoundly impacted individuals to be effectively included in clinical trials and result in better DEE treatments. Caregivers of children with DEEs understand firsthand that clinical tools intended to measure non-seizure outcomes, like communication and motor skills, were not designed for and don't work for their children. More sensitive tools are needed to measure the small changes that occur in DEEs. The limitations of existing measurement tools for DEEs have significant consequences: - Non-seizure responses to new therapies cannot be measured without tools designed specifically for individuals with severe to profound intellectual disability.- If a response cannot be measured in a trial, a potentially beneficial impact will be missed and a therapy, having failed to demonstrate an effect, may not gain regulatory approval.- DEE-affected individuals are less likely to benefit from the wave of new disease-modifying therapies providing hope for many other rare genetic diseases. DEE-P Connections, a patient advocacy organization supporting families caring for those severely affected by DEEs, launched The Inchstone Project to address this problem. This team science research collaborative unites researchers, pharmaceutical companies, advocates and others around a shared vision of adapting existing tools to reliably capture the small but important changes in skills in those severely affected by DEEs. To better understand these gaps, the Inchstone team conducted a pilot study with 10 children with SCN2A DEE. The team administered multiple assessments to explore how to adapt the tools to better capture the abilities and growth of this population. The team also completed a comprehensive DEE-wide survey with over 270 caregivers documenting their children's abilities and priorities for their improvement from new treatments, helping to document how existing tools may be updated to better capture what's most important to families and measure their children's small but important improvements over time. The Inchstone Project is on course to assure those profoundly impacted by DEEs are meaningfully included in clinical trials by establishing trusted and reliable non-seizure measurement tools.

Global modified-Delphi consensus on comorbidities and prognosis of SCN8A-related epilepsy and/or neurodevelopmental disorders.

OBJECTIVES: We aimed to develop consensus on comorbidities (frequency, severity, and prognosis) and overall outcomes in epilepsy, development, and cognition for the five phenotypes of SCN8A-related disorders. METHODS: A core panel consisting of 13 clinicians, 1 researcher, and 6 caregivers was formed and split into three workgroups. One group focused on comorbidities and prognosis. All groups performed a literature review and developed questions for use in a modified-Delphi process. Twenty-eight clinicians, one researcher, and 13 caregivers from 16 countries participated in three rounds of the modified-Delphi process. Consensus was defined as follows: strong consensus ≥80% fully agree; moderate consensus ≥80% fully or partially agree, <10% disagree; and modest consensus 67%-79% fully or partially agree, <10% disagree. RESULTS: Consensus was reached on the presence of 14 comorbidities in patients with Severe Developmental and Epileptic Encephalopathy (Severe DEE) spanning non-seizure neurological disorders and other organ systems; impacts were mostly severe and unlikely to improve or resolve. Across Mild/Moderate Developmental and Epileptic Encephalopathy (Mild/Moderate DEE), Neurodevelopmental Delay with Generalized Epilepsy (NDDwGE), and NDD without Epilepsy (NDDwoE) phenotypes, cognitive and sleep-related comorbidities as well as fine and gross motor delays may be present but are less severe and more likely to improve compared to Severe DEE. There was no consensus on comorbidities in the SeL(F)IE phenotype but strong conesensus that seizures would largely resolve. Seizure freedom is rare in patients with Severe DEE but may occur in some with Mild/Moderate DEE and NDDwGE. SIGNIFICANCE: Significant comorbidities are present in most phenotypes of SCN8A-related disorders but are most severe and pervasive in the Severe DEE phenotype. We hope that this work will improve recognition, early intervention, and long-term management for patients with these comorbidities and provide the basis for future evidence-based studies on optimal treatments of SCN8A-related disorders. Identifying the prognosis of patients with SCN8A-related disorders will also improve care and quality-of-life for patients and their caregivers.

Global modified Delphi consensus on diagnosis, phenotypes, and treatment of SCN8A-related epilepsy and/or neurodevelopmental disorders.

OBJECTIVE: We aimed to develop consensus for diagnosis/management of SCN8A-related disorders. Utilizing a modified Delphi process, a global cohort of experienced clinicians and caregivers provided input on diagnosis, phenotypes, treatment, and management of SCN8A-related disorders. METHODS: A Core Panel (13 clinicians, one researcher, six caregivers), divided into three subgroups (diagnosis/phenotypes, treatment, comorbidities/prognosis), performed a literature review and developed questions for the modified Delphi process. Twenty-eight expert clinicians, one researcher, and 13 caregivers from 16 countries participated in the subsequent three survey rounds. We defined consensus as follows: strong consensus, ≥80% fully agree; moderate consensus, ≥80% fully/partially agree, <10% disagree; and modest consensus, 67%-79% fully/partially agree, <10% disagree. RESULTS: Early diagnosis is important for long-term clinical outcomes in SCN8A-related disorders. There are five phenotypes: three with early seizure onset (severe developmental and epileptic encephalopathy [DEE], mild/moderate DEE, self-limited (familial) infantile epilepsy [SeL(F)IE]) and two with later/no seizure onset (neurodevelopmental delay with generalized epilepsy [NDDwGE], NDD without epilepsy [NDDwoE]). Caregivers represented six patients with severe DEE, five mild/moderate DEE, one NDDwGE, and one NDDwoE. Phenotypes vary by age at seizures/developmental delay onset, seizure type, electroencephalographic/magnetic resonance imaging findings, and first-line treatment. Gain of function (GOF) versus loss of function (LOF) is valuable for informing treatment. Sodium channel blockers are optimal first-line treatment for GOF, severe DEE, mild/moderate DEE, and SeL(F)IE; levetiracetam is relatively contraindicated in GOF patients. First-line treatment for NDDwGE is valproate, ethosuximide, or lamotrigine; sodium channel blockers are relatively contraindicated in LOF patients. SIGNIFICANCE: This is the first-ever global consensus for the diagnosis and treatment of SCN8A-related disorders. This consensus will reduce knowledge gaps in disease recognition and inform preferred treatment across this heterogeneous disorder. Consensus of this type allows more clinicians to provide evidence-based care and empowers SCN8A families to advocate for their children.

FDA Patient-Focused Drug Development Guidances: Considerations for Trial Readiness in Rare Developmental and Epileptic Encephalopathies

Developmental and epileptic encephalopathies (DEE) are rare, often monogenic neurodevelopmental conditions. Most affected individuals have refractory seizures. All have multiple severe impairments which can be as life-limiting as or more limiting than the seizures themselves. Mechanism- and gene-targeted therapies for these individually rare, genetic conditions hold hope for treatment, amelioration of disease expression, and even cure. The near absence of fit-for-purpose (FFP) clinical outcome assessments (COA) to establish the benefits for nonseizure outcomes of these new therapies in clinical trials poses significant challenges to drug development. The Food and Drug Administration Patient-Focused Drug Development guidance series provides direction for how to overcome these challenges and to ensure FFP measures are available for trials. The goal is to have measures that address outcomes of importance to patients and caregivers, reliably and accurately measure the outcome in the spectrum of abilities for the target disease, and are sensitive to meaningful change over time. The guidances identify 3 primary strategies: (1) directly adopting and implementing available outcome measures; (2) creating measures de novo; and (3) a middle path of adapting or modifying existing measures. Emphasized throughout the guidances is the indispensable and extensive role of the patient or caregiver to assuring the goal of having fit measures is achieved. This review specifically considers the difficulties of adopting available COAs in severely impaired patient groups and ways to adapt or modify existing COAs to be FFP as encouraged in the guidances. Adaptations include alternative scoring, use of assessments in out-of-intended age ranges, and modifications for individuals with sensory or motor impairments. Some additional considerations that may facilitate achieving adequate clinical outcome measures, especially for rare diseases, include use of personalized endpoints, merging of existing COAs, and developing a consortium of rare DEE advocates and researchers to ensure fitness of adapted COAs across multiple rare disease groups. The FDA guidances help ensure that clinical trials targeting nonseizure outcomes, especially in severely impaired populations, will have adequately valid and sensitive outcome measures. This in turn will strengthen the ability of trials to provide informative tests of whether treatments provide meaningful therapeutic efficacy.

What does better look like in individuals with severe neurodevelopmental impairments? A qualitative descriptive study on SCN2A-related developmental and epileptic encephalopathy.

PURPOSE: There are limited psychometric data on outcome measures for children with Developmental Epileptic Encephalopathies (DEEs), beyond measuring seizures, and no data to describe meaningful change. This study aimed to explore parent perceptions of important differences in functional abilities that would guide their participation in clinical trials. METHODS: This was a descriptive qualitative study. Semi-structured one-on-one interviews were conducted with 10 families (15 parent participants) with a child with a SCN2A-DEE [8 male, median (range) age 7.5 (4.5-21)] years. Questions and probes sought to understand the child's functioning across four domains: gross motor, fine motor, communication, and activities of daily living. Additional probing questions sought to identify the smallest differences in the child's functioning for each domain that would be important to achieve, if enrolling in a traditional therapy clinical trial or in a gene therapy trial. Data were analyzed with directed content analysis. RESULTS: Expressed meaningful differences appeared to describe smaller developmental steps for children with more limited developmental skills and more complex developmental steps for children with less limited skills and were different for different clinical trial scenarios. Individual meaningful changes were described as important for the child's quality of life and to facilitate day-to-day caring. CONCLUSION: Meaningful change thresholds have not been evaluated in the DEE literature. This study was a preliminary qualitative approach to inform future studies that will aim to determine quantitative values of change, applicable to groups and within-person, to inform interpretation of specific clinical outcome assessments in individuals with a DEE.