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Evaluating GTX-102 for cognitive function in children with Angelman Syndrome

A Phase 3, Randomized, Double-blind, Sham-controlled Study Investigating the Efficacy and Safety of GTX-102 in Pediatric Subjects With Angelman Syndrome

Phase 3 Interventional Ultragenyx Pharmaceutical Inc · NCT06617429

This study is testing if a new treatment called GTX-102 can help improve thinking skills in children with Angelman Syndrome.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment120 (estimated)
Ages4 Years to 17 Years
SexAll
SponsorUltragenyx Pharmaceutical Inc Industry-sponsored
Locations31 sites (Los Angeles, California and 30 other locations)
Trial IDNCT06617429 on ClinicalTrials.gov

What this trial studies

This phase 3 clinical trial aims to assess the efficacy and safety of GTX-102 in improving cognitive function in pediatric patients diagnosed with deletion-type Angelman Syndrome. Participants will receive either GTX-102 or a sham treatment, and their progress will be monitored through various assessments. The study requires participants to have a confirmed genetic diagnosis and to be able to ambulate independently or with assistance. The trial will also involve scheduled visits and specific medical procedures to ensure safety and compliance.

Who should consider this trial

Good fit: Ideal candidates are children with a confirmed diagnosis of deletion-type Angelman Syndrome who can ambulate independently or with assistance.

Not a fit: Patients who primarily rely on a wheelchair for mobility will not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly enhance cognitive abilities in children with Angelman Syndrome.

How similar studies have performed: While this approach is novel, previous studies targeting cognitive function in Angelman Syndrome have shown promise, indicating potential for success.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion Criteria:

* Signed informed consent from parent(s) or legal guardian(s)
* Confirmed diagnosis of AS with genetic confirmation of full maternal ubiquitin-protein ligase E3A (UBE3A) gene deletion causing AS in the region of 15q11.2 q13
* Able to ambulate independently, or with assistance at the Screening Visit (note, a child whose primary means of mobility is by wheelchair is excluded from the study)
* Platelet count, prothrombin time / international normalized ratio, and partial thromboplastin time within 1.5x the normal limits at the Screening Visit
* Willing and able to comply with scheduled visits, drug administration plan, laboratory tests, and all study procedures, including LP procedure, MRI, and tolerating anesthesia without intubation
* From the time of informed consent through to at least 6 months after the final dose of GTX-102, females of childbearing potential who are sexually active must use highly effective contraception or abstinence. Males are able to participate if they agree to remain abstinent (refrain from heterosexual intercourse) or use acceptable contraceptive methods during the study and for at least 3 months after the final dose of GTX-102

Key Exclusion Criteria:

* Any change in medications or diet/supplements intended to treat symptoms of AS (eg, sleeping aids, antiseizure medications, supplements, dietary change including ketogenic or low-glycemic index diet, other) within the month prior to the Screening Visit (excluding weight-based adjustments)
* Any condition that creates an increased risk of unsuccessful LP
* Current or expected concomitant use of drugs that increase the risk of bleeding (eg, heparin, low molecular weight heparin, platelet inhibitors)
* Known hypersensitivity to GTX-102 or its excipients that, in the judgment of the Investigator, places the subject at increased risk for adverse effects
* Presence or history of any condition, lab abnormality, or infection, that, in the judgement of the Investigator, would interfere with participation, pose undue safety risk, or would confound interpretation of results
* Pregnant or breastfeeding or planning to become pregnant (self or partner) at any time during the study
* Use of any investigational product or investigational medical device within 6 months or 5 half-lives prior to the Screening Visit or any prior use of gene therapy or ASO regardless of duration since last administration
* Concurrent participation in any interventional study

Where this trial is running

Los Angeles, California and 30 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 → Find more trials like this →
Conditions Angelman Syndrome
Last reviewed 2026-06-13 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.