Encoded Therapeutics Raises $275M for Dravet Syndrome Gene Therapy ETX101

Encoded Raises $275M to Push a One-Time Gene Therapy for a Severe Childhood Epilepsy

Interim trial data showed up to 79% fewer monthly seizures after a single dose — and now Encoded Therapeutics has fresh funding to drive its Dravet syndrome gene therapy toward pivotal trials.

By iPharmag Editorial Desk · Sep 11, 2026 · 1 min read

Conceptual illustration of a gene therapy calming erratic neuronal signals in a child’s brain

Conceptual illustration. Encoded raised $275M for ETX101, a one-time gene therapy for Dravet syndrome.

Encoded Therapeutics has raised $275 million in Series F financing to advance ETX101, a one-time gene therapy for Dravet syndrome — a severe, hard-to-treat childhood epilepsy. The round was co-led by GV and a healthcare fund, with ARCH Venture Partners, Janus Henderson and Farallon participating.

The disease

Dravet syndrome is a devastating genetic epilepsy marked by prolonged seizures and developmental delays. More than 90% of cases trace to loss-of-function mutations in the SCN1A gene, and it occurs in roughly 1 in 16,000 births. Standard anti-seizure drugs often fall short.

The therapy

Rather than adding a whole new gene copy, ETX101 selectively boosts expression of the patient’s own healthy SCN1A gene — addressing the root genetic cause with a single administration. In the Phase 1/2 POLARIS study, interim data showed monthly seizure reductions of up to 79% after one dose, alongside encouraging developmental improvements.

Why it matters

A durable, one-time treatment would be transformative for families managing relentless seizures. Encoded plans pivotal trials in infants and young children, with expansion studies through age 18; a second asset, ETX301, targets an IND in 2027 for post-amputation nerve pain. As with all gene-therapy programs, interim results must hold up in larger, controlled trials. Not medical advice.

Frequently asked questions

How does ETX101 work?

Instead of delivering a full new gene, it selectively increases expression of the patient’s own healthy copy of the SCN1A gene — the gene mutated in most Dravet syndrome cases — in a single administration, targeting the root cause of the disease.

What did the interim data show?

In the Phase 1/2 POLARIS study, a single dose produced monthly seizure reductions of up to 79%, with encouraging developmental improvements. These are interim results that must be confirmed in larger pivotal trials.

This article is for general information only and is not medical advice. Consult a qualified healthcare professional for any medical decisions.