Join us Donate

Current Clinical Trials

This page is a curated list of interventional clinical trials relevant to people with Dravet syndrome in the UK and may not include all studies; families and carers should always discuss possible trial participation with their usual clinical team. Dravet Syndrome UK independently selects which clinical trials to list and how they are described; inclusion on this page does not imply endorsement of any specific study, treatment or company. For full information about these studies, including protocol details and current recruitment status, please see the official registry entry on ClinicalTrials.gov.

Anti-seizure treatments

Traditionally, treatment for Dravet Syndrome focuses on managing seizures.

 

DEE‑p SEA Study (NCT06660394)

The DEE‑p SEA study is evaluating bexicaserin as an oral treatment for motor seizures in individuals with developmental and epileptic encephalopathies (DEEs).

Investigational compound: Bexicaserin
Phase: 3
Age: 2–65 years
Locations: Glasgow (currently recruiting); London, Newcastle, Southampton (opening soon)
Sponsor: H. Lundbeck A/S

Study website: https://deepdsstudy.com/

Latest news (06/12/25): Results from the phase 1/2 open label extension showed a median reduction in countable motor seizures of -60.2% at ~18 months (n=30), and -53.7% at ~24 months (n=17). No new safety concerns were observed.

 

ARGUS Study (NCT04462770)

The ARGUS study aims to evaluate clemizole as an oral add-on therapy for seizures in people with SCN1A-confirmed Dravet syndrome.

Investigational compound: Clemizole HCl/ EPX-101
Phase: 3
Age: 2 years and older
Locations: Sheffield, London 
Sponsor: Harmony Biosciences

Study website: https://global.argustrial.com/

Latest news: (08/12/2025): Results from phase 3 open-label extension showed a median reduction of countable motor seizure frequency per 28 days of 50%, with 50% achieving this 50% reduction. EPX-100 was generally well-tolerated.

 

(Recruitment closed) ORCHID Study (NCT06118255)

The ORCHID study is investigating fenfluramine as an anti-seizure therapy in young children aged 1-2 years with suspected Dravet syndrome. OCHID Study (NCT06118255)

Investigational compound: Fenfluramine
Phase: 3
Age: 1-2 years
Locations: Glasgow, London
Sponsor: UCB

Study website: https://www.ucb.com/innovation/clinical-studies/current-studies?studyId=EP0213

Disease-modifying Treatments

As the understanding of Dravet syndrome and SCN1A mutations has progressed, new therapies are being developed to target the underlying mechanisms. There are currently two compounds in clinical trials investigating disease-modifying approaches in Dravet syndrome.

 

EXPEDITION Study (NCT06283212)

The EXPEDITION study is evaluating ETX‑101, a one‑time AAV9 based gene therapy, designed for children with SCN1A‑confirmed Dravet syndrome.

Investigational compound: ETX‑101
Phase: 1/2
Age: 6-48 months
Locations: Glasgow, London, Sheffield
Sponsor: Encoded Therapeutics

Study website: https://encoded.com/programs/clinical-studies/

Latest news (05/12/2025): Interim data from the phase I/II clinical trials  show the treatment was well tolerated across all dose levels. A 78% reduction in seizure frequency was seen on dose level 3, and clinically meaningful gains in neurodevelopment were seen across dose levels.

 

(Recruitment closed) EMPEROR Study (NCT06872125)

The EMPEROR study will assess zorevunersen, a disease‑modifying antisense therapy, in people with SCN1A-confirmed Dravet syndrome. This double‑blind, sham‑controlled trial will assess efficacy for reducing major motor seizures and improving cognition/behaviour over 52 weeks, with an open-label extension for eligible participants.

Investigational compound: Zorevunersen
Phase: 3

Age: 2-17 years

Locations: Sheffield, Glasgow, London

Sponsor: Stoke Therapeutics & Biogen

Study website: https://www.emperorstudy.com/en-GB

Latest news (05/12/2025):  Long-term results from the open-label extension show durable seizure reductions, including increases in seizure-free days, in addition to improvements in cognition, behaviour and quality of life. In the first analysis, deviations in progression from a matched cohort in the BUTTERFLY natural history study was seen.