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A Study of the Safety and Tolerability of GTX-102 in Children With Angelman Syndrome | Clinical Trials | Clareo Health

COMPLETEDPHASE1/PHASE2

A Study of the Safety and Tolerability of GTX-102 in Children With Angelman Syndrome

A Phase 1/2 Open-label, Multiple-dose, Dose-escalating Clinical Trial of the Safety and Tolerability of GTX-102 in Pediatric Patients With Angelman Syndrome (AS)

NCT04259281•Ultragenyx Pharmaceutical Inc

View on ClinicalTrials.gov

Summary

The primary objective of the study is to evaluate the safety and tolerability of multiple-ascending doses of GTX-102 administered by intrathecal (IT) injection to participants with Angelman Syndrome (AS).

Detailed Description

This is a Phase 1/2, open-label, multiple-dose, study to evaluate the safety, tolerability, and plasma and CSF concentrations of GTX-102 in pediatric participants with AS. The study includes a Loading phase followed by a Maintenance phase. Participants may continue on GTX-102 during the Maintenance phase of the study until GTX-102 is commercially available, intolerable toxicity occurs, the parent/legal guardian withdraws consent, the participant enrolls in another experimental study, or this study is terminated. This study was previously posted by GeneTX Biotherapeutics, LLC and was transferred to Ultragenyx in July 2022.

Eligibility

Age

4 - 17 years

Sex

ALL

Healthy Volunteers

Inclusion Criteria

•Signed informed consent from parent(s) or legal guardian(s)
•Documented genetic confirmation of full maternal UBE3A gene deletion causing AS in the region of 15q11.2-q13 including class I, II or III
•Stable seizure control (defined as clinically stable with no changes in antiepileptic medications over the prior 1 month before the screening visit, other than weight associated dose adjustments)
•Able to ambulate independently, or with an assistive device (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 1.2 x the normal limits
•Normal renal function with serum creatinine and spot urine protein ≤ 1.4 x the upper limit of normal (ULN)
•Normal hepatic function with total bilirubin, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase ≤ 1.4 x ULN. Exception: levels ≤ 2 × ULN are acceptable if due to anti-epileptic drugs (AEDs) or Gilbert syndrome
•Willing and able to comply with scheduled visits, drug administration plan, laboratory tests, study restrictions, and all study procedures, including LP procedure
•Able to tolerate the anesthetic regimen, if required for LP procedure
•A female patient is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies: Female of non-childbearing potential (ie, pre-menarche), Female of childbearing potential who agrees to remain abstinent (refrain from heterosexual intercourse) or use acceptable contraceptive methods during the treatment period and for at least 3 months after the final dose of GTX-102
+1 more criteria

Exclusion Criteria

•Any change in medications (excluding AEDs) or diet/supplements intended to treat symptoms of AS (eg, sleeping aids, supplements, dietary change including ketogenic or low-glycemic index diet, other) over the prior 1 month before screening
•Any bleeding or platelet disorder
•Any clinically significant cardiovascular, endocrine, hepatic, renal, pulmonary, gastrointestinal, neurological, malignant, metabolic, psychiatric, or other condition that, in the judgment of the Investigator, will pose a safety risk, make the patient unsuitable for participation in, and/or unable to complete the study procedures
•Any laboratory abnormality, that, in the Investigator's opinion, could adversely affect the safety of the patient, make it unlikely that the course of treatment or follow up would be completed, or impair the assessment of study result
•Known positive for hepatitis B virus, hepatitis C virus, or human immunodeficiency virus
•Any active infection
•Bone, spine, bleeding, or other disorder that exposes the patient to risk of injury or unsuccessful lumbar puncture
•Drugs that increase the risk of bleeding (eg, heparin, low molecular weight heparin, platelet inhibitors)
•Any prior use of gene therapy
•Use of any investigational drugs in the past 6 months or within 5 half-lives, whichever period is greater (with the exception of prior GTX 102)
+3 more criteria

Locations (25)

UCLA Medical Center

Los Angeles, California, United States

Rady Children's Hospital

San Diego, California, United States

Rare Disease Research

Atlanta, Georgia, United States

Rush University Medical Center

Chicago, Illinois, United States

Boston Children's Hospital

Boston, Massachusetts, United States

Weill Cornell Medicine

New York, New York, United States

Austin Health

Heidelberg, Victoria, Australia

The Royal Children's Hospital

Parkville, Victoria, Australia

Queensland Children's Hospital

South Brisbane, Australia

MAGIC Clinic Ltd

Calgary, Alberta, Canada

Key Dates

Start Date

February 24, 2020

Primary Completion Date

January 8, 2025

Completion Date

January 8, 2025

Last Updated

January 9, 2026

Enrollment

ACTUAL participants

Conditions

Angelman Syndrome

Interventions

GTX-102

DRUG

A Study to Investigate the Pharmacokinetics (PK) and Safety and to Provide Proof of Mechanism of Alogabat in Children and Adolescents Aged 5-17 Years With Angelman Syndrome (AS) With Deletion Genotype.

NCT05630066

Angelman Syndrome

View study

COMPLETEDPHASE1

A Study to Investigate the Safety, Tolerability, Pharmacokinetics (PK) and Pharmacodynamics (PD) of RO7248824 in Participants With Angelman Syndrome (AS)

NCT04428281

Angelman Syndrome

View study

COMPLETEDPHASE2

A Study in Adults and Adolescents With Angelman Syndrome (STARS)

Data Source & Attribution

This clinical trial information is sourced from ClinicalTrials.gov, a service of the U.S. National Institutes of Health.

ClinicalTrials.gov last update: January 9, 2026Data synced to Clareo: March 29, 2026

Modifications: This data has been reformatted for display purposes. Eligibility criteria have been parsed into inclusion/exclusion sections. Location data has been geocoded to enable distance-based search. For the authoritative and most current information, please visit ClinicalTrials.gov.

Neither the United States Government nor Clareo Health make any warranties regarding the data. Check ClinicalTrials.gov frequently for updates.

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A Study of the Safety and Tolerability of GTX-102 in Children With Angelman Syndrome

Inclusion Criteria

Exclusion Criteria

A Study to Investigate the Pharmacokinetics (PK) and Safety and to Provide Proof of Mechanism of Alogabat in Children and Adolescents Aged 5-17 Years With Angelman Syndrome (AS) With Deletion Genotype.

A Study to Investigate the Safety, Tolerability, Pharmacokinetics (PK) and Pharmacodynamics (PD) of RO7248824 in Participants With Angelman Syndrome (AS)

A Study in Adults and Adolescents With Angelman Syndrome (STARS)

Angelman Syndrome Natural History Study-FAST UK

A Study of OV101 in Individuals With Angelman Syndrome (AS)

Study on the Brain Network of Angelman Syndrome