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.