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ION337

Phase 1

Dravet Syndrome | Small molecule | Neurology |Ionis Pharmaceuticals, Inc.|Last Updated: Sep 3, 2026

Success Probability

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Market & Valuation

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Trial Design

CONTROLLEDDMC
Total Trials1
Total Enrollment32

FDA Designations

No designations recorded

Clinical trial landscape

ION337 · 1 trial · 1 indication

Phase 1 1
NCT07531745ASCEND: Safety and Tolerability of ION337 for the Treatment of Dravet SyndromeDravet Syndrome
RECRUITING32 Analytics
PHASE1RECRUITING
ASCEND: Safety and Tolerability of ION337 for the Treatment of Dravet Syndrome
Dravet SyndromeUnlock trial analytics

Study Endpoints

Primary Endpoints

Parts 1 and 2: Number of Participants with Treatment-emergent Adverse Events (TEAEs) and Serious TEAEs
Part 1: up to 6 months; Part 2: up to 31 months
Number of Participants With Clinically Significant Change From Baseline in Safety Laboratory Values
Part 1: up to 6 months; Part 2: up to 31 months
Parts 1 and 2: Number of Participants With Clinically Significant Change From Baseline in Vital Signs
Part 1: up to 6 months; Part 2: up to 31 months
Parts 1 and 2: Number of Participants With Clinically Significant Change From Baseline in Electrocardiogram (ECG)
Part 1: up to 6 months; Part 2: up to 31 months
Parts 1 and 2: Number of Participants With Clinically Significant Change From Baseline in Physical and Neurological Examination Findings
Part 1: up to 6 months; Part 2: up to 31 months
Parts 1 and 2: Number of Participants with Change in Columbia Suicidality Severity Rating Scale (C-SSRS)
Part 1: up to 6 months; Part 2: up to 31 months

Secondary Endpoints

Pharmacokinetic (PK) Parameters Measure Description: Analysis of plasma concentrations of ION337
Pre-Dose Day 1 (Dosing) until 6 months after dosing in Part 1 and up to 31 months in Part 2
Exposure of ION337 in Cerebrospinal Fluid (CSF) Measure Description: Measurement of ION337 concentrations
Pre-dose Day 1 (Dosing) until 6 months after dosing in Part 1 and up to 31 months in Part 2
Parts 1 and 2: Percent Change From Baseline in 28-day Normalized Major Motor Seizure (MMS) Frequency
Part 1: up to 6 months; Part 2: up to 31 months
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Study Design & Arms

AllocationNON_RANDOMIZED
MaskingNONE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Part 1: Single Ascending Dose (SAD): Dose Level 1EXPERIMENTALParticipants aged 2 to ≤ 12 years will receive a single intrathecal bolus (ITB) injection of ION337.
Part 1: SAD: Dose Level 2EXPERIMENTALParticipants aged 2 to ≤ 12 will receive a single dose of ION337.
Part 1: SAD: Dose Level 3EXPERIMENTALParticipants aged 2 to ≤ 12 will receive a single dose of ION337.
Part 1: SAD: Dose Level 4EXPERIMENTALParticipants aged 2 to ≤ 12 will receive a single dose of ION337.
Part 2: Multiple Ascending Dose (MAD): Dose Level 1-4EXPERIMENTALOnly participants who complete Part 1 will be eligible to participate in Part 2. Participants will receive multiple doses of ION337. Participants will begin treatment at the same dose level assigned in Part 1.

Interventions

NameTypeDescription
ION337DRUGION337 will be administered by ITB injection.
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Eligibility Criteria

Age Range2 Years to 12 Years
SexALL
Healthy VolunteersNo
Study Sites6

Key Inclusion Criteria: 1. Participant is aged ≥ 2 to ≤ 12 years old at the time of informed consent. 2. Participant has at least 1 parent or caregiver ≥ 18 years old who is willing and able to provide informed consent (signed and dated) and attend all scheduled study visits. 3. Has a documented di...

Countries:United StatesCanada
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Recent Changes (Last 90 Days)

LOWSep 3, 2026NCT07531745lastUpdatePostDate: changed
LOWSep 3, 2026NCT07531745lastUpdatePostDate: changed
LOWAug 5, 2026NCT07531745lastUpdatePostDate: changed
LOWJun 23, 2026NCT07531745startDate: changed
LOWJun 23, 2026NCT07531745startDate: changed

Frequently asked questions about ION337

What is ION337 used for in Dravet Syndrome?

ION337 is an investigational small molecule being developed for the treatment of Dravet Syndrome, a severe form of childhood epilepsy. It is currently in Phase 1 clinical development and has not been approved by regulatory authorities. The drug is being studied to evaluate its safety and tolerability in patients with this condition.

Who makes ION337?

ION337 is being developed by Ionis Pharmaceuticals, Inc., a biopharmaceutical company traded on NASDAQ under the ticker symbol IONS. The company is conducting clinical research on this investigational drug for Dravet Syndrome, with the drug currently in Phase 1 development.

What phase is ION337 in?

ION337 is currently in Phase 1 clinical development. It is an investigational drug and has not received regulatory approval. The ongoing Phase 1 trial is recruiting participants to evaluate the safety and tolerability of ION337 in patients with Dravet Syndrome.

What clinical trials is ION337 in?

ION337 is being studied in the ASCEND trial, registered as NCT07531745, a Phase 1 study titled "ASCEND: Safety and Tolerability of ION337 for the Treatment of Dravet Syndrome." This recruiting trial has an estimated enrollment of 32 participants and is being conducted in the United States and Canada.

Is ION337 FDA approved?

ION337 is not FDA approved. It is an investigational drug currently in Phase 1 clinical development for Dravet Syndrome. The ongoing clinical trial is designed to assess the safety and tolerability of the drug, and it has not yet completed the clinical development process required for regulatory approval.