A Safety and Efficacy Study of GTX-102 in Subjects With Deletion- or Nondeletion-type Angelman Syndrome (AS)
Aurora
A Phase 2, Open-label, Basket Study Investigating the Safety and Efficacy of GTX-102 in Adult and Pediatric Subjects With Deletion- or Nondeletion-type Angelman Syndrome
2 other identifiers
interventional
60
8 countries
22
Brief Summary
The main goal of the study is to evaluate the safety and efficacy of GTX-102 in participants with Angelman syndrome.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P50-P75 for phase_2
Started Oct 2025
Typical duration for phase_2
22 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
Click on a node to explore related trials.
Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
August 21, 2025
CompletedFirst Posted
Study publicly available on registry
September 5, 2025
CompletedStudy Start
First participant enrolled
October 13, 2025
CompletedPrimary Completion
Last participant's last visit for primary outcome
January 1, 2030
ExpectedStudy Completion
Last participant's last visit for all outcomes
January 1, 2030
April 24, 2026
April 1, 2026
4.2 years
August 21, 2025
April 23, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (4)
Subprotocol A/B/C/D: Number of Participants with Treatment Emergent Adverse Events (TEAEs) and Serious Adverse Events (SAEs), Severe Events, and Events Related to Investigational Product, Procedure, and Premedication
Up to Day 506
Subprotocol A Only: Bayley-4 Cognitive Without Caregiver Input Raw Score Change from Baseline at Day 338
Baseline, Day 338
Subprotocol B/D Only: Multidomain Responder Index (MDRI) Net Response at Day 338
The following assessments will be included to calculate the MDRI net response: Bayley-4 Cognitive and Receptive Communication, Aberrant Behavior Checklist- Community (ABC-C) Hyperactivity/Noncompliance (H/N), Angelman Severity Assessment (ASA) Sleep, ASA Gross Motor. For each assessment a meaningful score difference (MSD) is defined. A single net response score per participant will be derived accordingly, and a summary measure of net response will then be calculated across all participants.
Baseline, Day 338
Subprotocol C Only: MDRI Net Response at Day 338
The following assessments will be included to calculate the MDRI net response: Vineland-3 Expressive and Receptive Communication, ABC-C Irritability, ASA Gross Motor. For each assessment a meaningful score difference (MSD) is defined. A single net response score per participant will be derived accordingly, and a summary measure of net response will then be calculated across all participants.
Baseline, Day 338
Secondary Outcomes (9)
Subprotocol A/B/D Only: Change From Baseline at Day 338 in Bayley-4 Receptive Communication Raw Score
Baseline, Day 338
Subprotocol A/B/D Only: Change From Baseline at Day 338 in Bayley-4 Gross Motor Raw Score
Baseline, Day 338
Subprotocol B/D Only: Change From Baseline at Day 338 in Bayley-4 Cognitive Raw Score
Baseline, Day 338
Subprotocol B/C/D Only: Change From Baseline at Day 338 in Vineland-3 Receptive Communication Raw Score
Baseline, Day 338
Subprotocol B/C/D Only: Change From Baseline at Day 338 in Vineland-3 Expressive Communication Raw Score
Baseline, Day 338
- +4 more secondary outcomes
Study Arms (5)
Subprotocol A GTX-102
EXPERIMENTALParticipants with deletion-type Angelman syndrome, ≥1 to \<4 years of age will receive increasing doses of GTX-102 via intrathecal (IT) injection until the target dose is achieved. Dosing occurs every 3 months (Q3M) thereafter.
Subprotocol B GTX-102
EXPERIMENTALParticipants with paternal uniparental disomy (UPD)/imprinting center defect (ICD) Angelman syndrome, ≥4 to \<18 years of age will receive increasing doses of GTX-102 via IT injection until the target dose is achieved. Dosing occurs Q3M thereafter.
Subprotocol C GTX-102
EXPERIMENTALParticipants with all genotypes of Angelman syndrome, ≥18 to \<65 years of age will receive increasing doses of GTX-102 via IT injection until the target dose is achieved. Dosing occurs Q3M thereafter.
Subprotocol D GTX-102
EXPERIMENTALParticipants with mutation-type Angelman syndrome, ≥4 to \<18 years of age will receive increasing doses of GTX-102 via IT injection until the target dose is achieved. Dosing occurs Q3M thereafter.
Subprotocol D No Intervention then GTX-102
EXPERIMENTALParticipants with mutation-type Angelman syndrome, ≥4 to \<18 years of age will receive no treatment during the initial period. At the end of the no treatment period, participants will receive increasing doses of GTX-102 via IT injection until the target dose is achieved. Dosing occurs Q3M thereafter.
Interventions
During the no treatment period participants do not receive any study drug
antisense oligonucleotide
Eligibility Criteria
You may qualify if:
- Signed informed consent from parent(s) or legal guardian(s)
- Males and females of the following ages and genotypes at time of informed consent:
- Subprotocol A: ≥ 1 to \< 4 years of age with a genetically confirmed diagnosis of deletion-type Angelman syndrome
- Subprotocol B: ≥ 4 to \< 18 years of age with a genetically confirmed diagnosis of UPD/ICD Angelman syndrome
- Subprotocol C: ≥ 18 to \< 65 years of age with a genetically confirmed diagnosis of Angelman syndrome, any genotype
- Subprotocol D: ≥ 4 to \< 18 years of age with a genetically confirmed diagnosis of mutation-type Angelman syndrome
- Weight ≥ 8 kg at Screening Visit
- Platelet count, prothrombin time / international normalized ratio, and partial thromboplastin time \< 1.5x the upper limit of normal and platelets \> 75,000 cells/mm3 at the Screening Visit
- Willing and able to comply with scheduled visits, drug administration plan, laboratory tests, and all study procedures, including lumbar puncture (LP) procedure, magnetic resonance imaging (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
You may not qualify if:
- Any change in medications or diet/supplements intended to treat symptoms of Angelman Syndrome (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 lumbar puncture
- 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 or required premedication 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 judgment of the Investigator, would interfere with study 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 an ASO regardless of length of time since last use
- Concurrent participation in any interventional study
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (22)
Cedars Sinai Medical Center
Los Angeles, California, 90048, United States
Rush University Medical Center
Chicago, Illinois, 60612, United States
Clinical Trial Site
Baltimore, Maryland, 21205, United States
Clinical Trial Site
Kansas City, Missouri, 64108, United States
Rare Disease Research
Hillsborough, North Carolina, 27278, United States
Akron Children's Hospital
Akron, Ohio, 44308, United States
Clinical Trial Site
Philadelphia, Pennsylvania, 19104, United States
UT Health Austin
Austin, Texas, 78723, United States
Carum Research Inc.
Dallas, Texas, 75243, United States
Clinical Trial Site
Pilar, Buenos Aires, Argentina
Clinical Trial Site
Curitiba, Paraná, Brazil
Clinical Trial Site
Santa Cecília, Porto Alegre, Brazil
Clinical Trial Site
Marseille, France
Clinical Trial Site
Paris, France
Clinical Trial Site
Ramat Gan, Israel
Azienda Ospedaliera Universitaria Meyer IRCCS
Florence, Italy
Fondazione IRCCS Istituto Neurologico C. Besta
Milan, Italy
Clinical Trial Site
Rome, Italy
Hospital de Santa Maria
Lisbon, Portugal
Hospital Santa Joao
Porto, Portugal
Clinical Trial Site
London, United Kingdom
Clinical Trial Site
Oxford, United Kingdom
Related Links
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Study Officials
- STUDY DIRECTOR
Medical Director
Ultragenyx Pharmaceutical Inc
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 2
- Allocation
- RANDOMIZED
- Masking
- NONE
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
August 21, 2025
First Posted
September 5, 2025
Study Start
October 13, 2025
Primary Completion (Estimated)
January 1, 2030
Study Completion (Estimated)
January 1, 2030
Last Updated
April 24, 2026
Record last verified: 2026-04
Data Sharing
- IPD Sharing
- Will not share