Encoded Therapeutics Announces UK CTA Approval for Dravet Syndrome Gene Therapy Candidate ETX101

Initial study in the UK, EXPEDITION, will focus on infants and young children

EXPEDITION will begin in mid-2024 and will run concurrently with previously announced US and Australian clinical studies

SOUTH SAN FRANCISCO, Calif.–(BUSINESS WIRE)–Encoded Therapeutics Inc., a biotechnology company focused on developing genetic medicines for severe central nervous system (CNS) disorders, today announced the approval of its Clinical Trial Authorisation (CTA) application by the United Kingdom (UK) Medicines and Healthcare products Regulatory Agency (MHRA) for the EXPEDITION Study of ETX101 as a potential treatment for children with SCN1A+ Dravet syndrome. Dravet syndrome is the most common developmental and epileptic encephalopathy and is characterized by a spectrum of clinical symptoms, including treatment-resistant seizures and neurodevelopmental stagnation.

The UK CTA for EXPEDITION is part of a global regulatory strategy established by Encoded for clinical development of ETX101, which also includes regulatory clearance for an investigational new drug (IND) application in the United States and approval under the Clinical Trial Approval (CTA) scheme in Australia.

“This CTA marks the third regulatory approval for ETX101 as we advance our global clinical development program, POLARIS, to bring this potential one-time AAV gene regulation therapy to people affected by SCN1A+ Dravet syndrome around the world,” said Sal Rico, M.D., Ph.D., Chief Medical Officer of Encoded. “We believe ETX101 has the potential to deliver transformative benefit in multiple disease domains and have designed our clinical program to efficiently assess its impact on affected infants and young children. We are committed to working closely with our highly experienced investigators to expeditiously enroll affected children in an effort to advance therapeutic options for people living with Dravet syndrome.”

Professor Andreas Brunklaus, M.D., Ph.D., EXPEDITION Principal Investigator, and Consultant Paediatric Neurologist at the Royal Hospital for Children, Glasgow, UK, said, “In launching the EXPEDITION trial, we aim to confront the urgent need to develop disease modification strategies for children battling Dravet syndrome in the UK. The relentless and devastating nature of this condition underscores the critical importance of developing therapies that not only alleviate symptoms but also target the underlying mechanisms. EXPEDITION represents a significant stride forward in our collective pursuit of new treatments that can truly make a difference in the lives of people affected by Dravet syndrome.”


EXPEDITION is part of Encoded’s global clinical development program, POLARIS, and is a Phase 1/2 dose escalation study of ETX101 in children aged 6 months to <4 years with SCN1A+ Dravet syndrome in the UK. Up to two doses of ETX101 will be evaluated in 4 participants. The primary aims of the study are to evaluate the safety and tolerability of ETX101, to evaluate preliminary efficacy, and to contribute to therapeutic dose selection. EXPEDITION is expected to commence in the UK in mid-2024 and will run concurrently with clinical trials in the US (ENDEAVOR) and Australia (WAYFINDER).

About Encoded’s ETX101 Clinical Development Program POLARIS

POLARIS is built upon Encoded’s comprehensive preclinical research, and incorporates a multipronged biomarker discovery program (ELUCIDATE), patient-focused drug development initiatives (Dravet ENGAGE), and the recently completed natural history study (ENVISION), the largest prospective, longitudinal natural history study of Dravet patients to date. This foundational work has enabled optimization of POLARIS’ rigorous clinical design, including the ENDEAVOR (US), WAYFINDER (Australia) and EXPEDITION (UK) studies, to assess the safety and preliminary efficacy of ETX101 in infants and young children with SCN1A+ Dravet syndrome.

About ETX101

ETX101 is a potential one-time, disease-modifying gene regulation therapy targeting the underlying cause of SCN1A+ Dravet syndrome. In ETX101, a transgene encoding an engineered transcription factor under the control of a cell-selective regulatory element is delivered within a clinically-validated capsid (AAV9) to upregulate, or increase, the expression of the endogenous SCN1A gene. This approach is expected to increase production of NaV1.1 protein sodium channels in target neurons in the brain, leading to restored function. By targeting the underlying mechanism, ETX101 has the potential to address the full range of symptoms associated with Dravet syndrome.

About Dravet Syndrome

Dravet syndrome is a severe, lifelong disorder of the central nervous system that occurs in approximately 1 in 16,000 births worldwide, with the majority of cases resulting from loss-of-function variants in the SCN1A gene. This developmental and epileptic encephalopathy equally affects people of both sexes and all races, manifesting in a wide array of symptoms. Frequent, prolonged, and treatment-resistant seizures primarily begin in the first year of life of a typically developing infant. Severe cognitive and developmental stagnation, sleep abnormalities, motor impairment and behavioral difficulties usually manifest by the second or third year of a child’s life. More information about Dravet syndrome can be found at www.dravetfoundation.org.

About Encoded Therapeutics

Encoded Therapeutics is creating one-time, potentially disease-modifying gene therapies to improve the lives of people with severe CNS disorders. Our cell-selective targeting and regulation platform offers potentially unprecedented gene specificity and cell selectivity to unlock novel opportunities by targeting a range of disease mechanisms. We are overcoming key limitations of current gene therapies by incorporating platform innovations into therapeutic development and advancing potentially best-in-class programs in Dravet syndrome and additional CNS disorders. For more information, please visit www.encoded.com.


Jennifer Gorzelany

[email protected]

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