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Evaluating ION582 for treating Angelman Syndrome

Phase 3 Study of the Efficacy and Safety of ION582 in Children and Adults With Angelman Syndrome

PHASE3 · Ionis Pharmaceuticals, Inc. · NCT06914609

This study is testing a new treatment called ION582 to see if it can help people with Angelman syndrome caused by specific gene changes, focusing on both kids and adults.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment158 (estimated)
Ages2 Years to 50 Years
SexAll
SponsorIonis Pharmaceuticals, Inc. (industry)
Locations38 sites (Los Angeles, California and 37 other locations)
Trial IDNCT06914609 on ClinicalTrials.gov

What this trial studies

This Phase 3 study assesses the efficacy and safety of ION582 in individuals with Angelman syndrome caused by UBE3A gene mutations or deletions. It involves a randomized, double-blind, placebo-controlled design with two cohorts: pediatric participants aged 2 to less than 18 years and adult participants aged 18 to 50 years. The study includes a screening period, a 60-week treatment phase, a long-term extension phase, and a post-extension follow-up. Participants will be randomized to receive either ION582 at two different doses or a placebo during the treatment period.

Who should consider this trial

Good fit: Ideal candidates are children and adults aged 2 to 50 years with a confirmed diagnosis of Angelman syndrome due to UBE3A gene mutations or deletions.

Not a fit: Patients with Angelman syndrome not caused by UBE3A mutations or deletions may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve the quality of life for patients with Angelman syndrome.

How similar studies have performed: While there have been studies on treatments for Angelman syndrome, this specific approach with ION582 is novel and has not been previously tested.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion Criteria:

1. The participants caregiver(s)/ legally authorized representative must have given written informed consent and any authorizations required by local law and be able to comply with all study requirements.
2. Medically stable and can undergo sedation and/or general anesthesia without intubation.
3. Male or female between 2 and lesser than or equal to (≤)50 years of age, depending on specific cohort, at the time of the in-clinic Screening visit.
4. Participant has a clinical diagnosis of Angelman syndrome (AS) with molecular confirmation of either Ubiquitin-protein ligase E3A (UBE3A) deletion or UBE3A mutation.
5. Currently receiving stable doses of concomitant medications typically prescribed for AS, such as anti-epileptic medication, behavioral management medications, sleep medications, gabapentin, cannabidiol, and special diets, supplements, or nutritional support for at least 8 weeks prior to the Baseline visit.
6. Legally authorized representative/caregiver(s) agree(s) not to post any of the participant's personal medical data or information related to the study on any website or social media site (e.g., Facebook, Instagram, X (formerly Twitter), YouTube, TikTok, etc.) from the time of enrollment until they are notified that the study is completed.

Key Exclusion Criteria:

1. Must not have any clinically significant abnormalities in medical history (e.g., major surgery within 3 months of screening), or on physical examination for which treatment with an antisense oligonucleotide (ASO) would be contraindicated or which, in the opinion of the Principal Investigator (PI), could confound the results of this study.
2. Known brain or spinal disease that would interfere with the lumbar puncture (LP) procedure, cerebrospinal fluid (CSF) circulation, or presence of other factors would affect the safety of the LP procedure.
3. Must not have any other conditions, which, in the opinion of the Investigator, would make the participant unsuitable for inclusion or could interfere with the participant participating in or completing the study.
4. Must not have any laboratory abnormalities or any other clinically significant abnormalities that would, as assessed by the Investigator, at screening or Baseline, render a participant unsuitable for inclusion.
5. Previous treatment with an oligonucleotide (including small interfering ribonucleic acid (RNA) \[siRNA\], ASOs) gene therapy or gene editing. This exclusion criterion does not apply to approved nucleic acid-based vaccines, including mRNA vaccines, which are allowed.
6. Has molecular confirmation of AS due to paternal uniparental disomy, imprinting center defect, or mosaic findings.

Other inclusion/exclusion criteria may apply.

Where this trial is running

Los Angeles, California and 37 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Angelman Syndrome, ION582

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.