Current Clinical Trials

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: Lundbeck

Study website: https://deepdsstudy.com/

Latest news (25/08/25): Results from the phase 1/2 open label extension showed a median reduction of 59.3% in countable motor seizure frequency with 55% of participants having reductions greater than 50%. Bexicaserin was well tolerated, with no new safety signals 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
Phase: 3
Age: 2 years and older
Locations: Cardiff, Sheffield, London (Liverpool opening soon)
Sponsor: Harmony Biosciences

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

(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 (02/09/2025): ETX101 has received the U.S. FDA’s Regenerative Medicine Advanced Therapy (RMAT) designation. While not yet influencing UK regulatory pathways directly, this reflects encouraging early data.

Upcoming 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
Sponsor: Stoke Therapeutics & Biogen

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

Latest news (02/09/2025):  Long-term data from the zorevunersen open-label extension show substantial, durable reductions in convulsive seizures, alongside clear improvements in cognition and behaviour. The most common study drug related ‘treatment emergent adverse event’ was CSF protein elevations but no related clinical manifestations were observed.