RecruitingPhase 2

A Safety and Efficacy Study of GTX-102 in Subjects With Deletion- or Nondeletion-type Angelman Syndrome (AS)

United States60 participantsStarted 2025-10-13

Plain-language summary

The main goal of the study is to evaluate the safety and efficacy of GTX-102 in participants with Angelman syndrome.

Who can participate

Age range1 Year – 64 Years

SexALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

✓. 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

Exclusion criteria

✕. 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

What they're measuring

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

Timeframe: Up to Day 506

Subprotocol A Only: Bayley-4 Cognitive Without Caregiver Input Raw Score Change from Baseline at Day 338

Timeframe: Baseline, Day 338

Subprotocol B/D Only: Multidomain Responder Index (MDRI) Net Response at Day 338

Timeframe: Baseline, Day 338

Subprotocol C Only: MDRI Net Response at Day 338

Timeframe: Baseline, Day 338

Trial details

NCT IDNCT07157254

SponsorUltragenyx Pharmaceutical Inc

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2030-01

Contact for this trial

Patients Contact Trial Recruitment

1-888-756-8657 Trialrecruitment@ultragenyx.com

View on ClinicalTrials.gov More Angelman Syndrome trials

Who can participate

Age range1 Year – 64 Years

SexALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion criteria

✓. 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

Exclusion criteria

✕. 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

What they're measuring

Timeframe: Up to Day 506

Subprotocol A Only: Bayley-4 Cognitive Without Caregiver Input Raw Score Change from Baseline at Day 338

Timeframe: Baseline, Day 338

Subprotocol B/D Only: Multidomain Responder Index (MDRI) Net Response at Day 338

Timeframe: Baseline, Day 338

Subprotocol C Only: MDRI Net Response at Day 338

Timeframe: Baseline, Day 338