In short
ION337 is an investigational antisense oligonucleotide being studied for the treatment of Dravet syndrome, a rare and severe form of epilepsy that begins in infancy. It is not yet an authorised medicine. The only registered clinical trial is a Phase 1/2 study that has been authorised and plans to enrol 32 participants to assess safety and tolerability.
Key points
- ION337 is an investigational substance with no marketing authorisation.
- The condition studied is Dravet syndrome, a rare genetic epilepsy.
- The only registered trial is Phase 1/2, combining single and multiple ascending doses.
- The trial is authorised and plans to enrol 32 participants.
- The medicine is given by intrathecal use, meaning injection into the fluid around the spinal cord.
- The trial measures safety and tolerability, including treatment-emergent adverse events and serious adverse events.
What is ION337?
ION337 is an investigational antisense oligonucleotide. It is being developed for the treatment of Dravet syndrome, a rare and severe genetic epilepsy that begins in infancy. The substance has no marketing authorisation in the registry records, meaning it is not yet approved as a medicine. ION337 is the development code used for this substance.
How does ION337 work?
The registry record does not describe the molecular target or mechanism of action of ION337. As an antisense oligonucleotide, it belongs to a class of substances designed to bind to specific RNA molecules and modify gene expression, but the precise target in Dravet syndrome is not stated in the trial data. The trial itself is focused on safety and tolerability rather than on demonstrating a mechanism.
Which conditions is ION337 studied for?
- Dravet syndrome — a rare and severe form of epilepsy that begins in infancy and is associated with frequent, prolonged seizures and developmental delay. This is the only condition listed in the registered trial.
How is ION337 given?
ION337 is given by intrathecal use, meaning it is injected into the fluid that surrounds the spinal cord. The trial record lists the intervention as a drug for intrathecal use. No other pharmaceutical forms or routes of administration are described in the data.
What do the clinical trials show?
There is one registered clinical trial of ION337. It is a Phase 1/2 study titled "Safety and Tolerability of ION337 for the Treatment of Dravet Syndrome". The trial is authorised, meaning it has received approval to proceed, and it plans to enrol 32 participants. The study is interventional and is divided into two parts: Part 1 is a single ascending dose (SAD) part, and Part 2 is a multiple ascending dose (MAD) part.
The primary outcome measure is the incidence of treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs), together with clinically significant changes from baseline in safety laboratory values, vital signs, electrocardiograms (ECGs), physical and neurological examination measures, and the Columbia-Suicide Severity Rating Scale (C-SSRS). These are summarised by study part. The trial therefore measures safety and tolerability rather than effectiveness against seizures.
The registry record does not list detailed eligibility criteria such as age range, seizure frequency, or genetic confirmation of the SCN1A variant that causes most cases of Dravet syndrome. The brief summary states only that the objective is to evaluate the safety and tolerability of ION337.
What side effects are known?
No side effects of ION337 are described in the available sources. The registered trial is designed to detect and measure treatment-emergent adverse events and serious adverse events, but no results or specific side effect profiles have been published in the data provided.