Developmental and Epileptic Encephalopathy

This (DEEp OCEAN Study) is a double-blind, randomized, placebo-controlled, multicenter study to investigate the efficacy, safety, and tolerability of LP352 in the treatment of seizures in children and adults with DEE. The study consists of 3 main phases: Screening, Titration period, Maintenance period, followed by a Taper period and Follow-Up. The total duration of the study will be approximately 24 months.

This study focuses on children with Developmental and Epileptic Encephalopathy (DEE), a severe form of epilepsy that often has a genetic origin. Currently, standard diagnostic tools-known as short-read genome sequencing-fail to provide a diagnosis for over 50% of affected patients because they cannot detect certain complex DNA abnormalities. The purpose of this study is to evaluate the effectiveness of a newer, more advanced technology called Long-read Genome Sequencing (lrWGS). Unlike traditional methods, this technology analyzes very long fragments of DNA, allowing researchers to identify genetic errors that were previously "invisible." The study aims to answer whether Long-read Sequencing can successfully identify the genetic cause of epilepsy in patients who have already received a negative result from standard testing. By finding these missing answers, the research seeks to enable personalized medical treatments, improve genetic counseling for families, and advance our understanding of how these complex neurological conditions develop.

Developmental and Epileptic Encephalopathy (DEE) are a heterogeneous group of neurodevelopmental disorders linked to both epilepsy and its underlying etiology, independently of epileptiform activity. The creation of a database with retrospective follow-up of a large number of patients on a national scale will enable better knowledge of specific biomarkers, and thus a better classification and understanding of the natural evolution of DEE according to their etiology. This will enable better, more personalized therapeutic management of patients, depending on etiology and the presence or absence of these biomarkers. The investigators will also be able to draw up management recommendations, which are currently non-existent.