Long-term Extension of GTX-102 in Angelman Syndrome

A Long-term Extension Trial Investigating the Safety and Efficacy of GTX-102 in Patients With Angelman Syndrome

The primary objective of the study is to evaluate the long-term safety profile of GTX-102 in participants with Angelman Syndrome (AS)

Study Overview

• Status: Enrolling by invitation
• Conditions: Angelman Syndrome
• Intervention / Treatment: Drug: GTX-102

Detailed Description

This study is a phase 3, long term extension (LTE) which is open to participants rolling over from a prior GTX-102 clinical study. The LTE study will evaluate the long-term safety and efficacy of GTX-102 in participants with AS.

• Study Type: Interventional
• Enrollment (Estimated): 255
• Phase: Phase 3

Contacts and Locations

Study Locations

• Australia
  • Queensland
    • South Brisbane, Queensland, Australia, 4101
      • Queensland Children's Hospital
  • Victoria
    • Melbourne, Victoria, Australia, 3052
      • The Royal Children's Hospital
• Canada
  • Alberta
    • Calgary, Alberta, Canada, T2E 7Z4
      • MAGIC Clinic Ltd
  • British Columbia
    • Vancouver, British Columbia, Canada, V6H 3V4
      • British Columbia Children's Hospital
  • Ontario
    • London, Ontario, Canada, N6A 5W9
      • Childrens Hospital London Health Sciences Centre
    • Ottawa, Ontario, Canada, K1H 8L1
      • Childrens Hospital of Eastern Ontario
  • Quebec
    • Montreal, Quebec, Canada, H3G 1A4
      • The Research Institute of the McGill University Health Centre
• France
  • Marseille, France, 13385
    • AP-HM - Hôpital de la Timone
  • Paris, France, 75015
    • AP-HP Hopital Necker-Enfants Malades
• Germany
  • Hamburg, Germany, 20246
    • Universitaetsklinikum Hamburg-Eppendorf
  • Leipzig, Germany, 04103
    • Universitaetsklinikum Leipzig
• Israel
  • Ramat Gan, Israel, 5265601
    • Sheba Medical Center
• Spain
  • Majadahonda, Spain, 28222
    • Hospital Universitario Puerta de Hierro
  • Sabadell, Spain, 08208
    • Corporacio Sanitaria Parc Tauli - Hospital de Sabadell
• United Kingdom
  • Cambridge, United Kingdom, CB2 0QQ
    • University of Cambridge
  • London, United Kingdom, WC1N 3JH
    • Great Ormond Street Hospital for Children
  • Oxford, United Kingdom, OX3 9DU
    • Oxford University Hospitals NHS Foundation Trust
• United States
  • California
    • Los Angeles, California, United States, 90095
      • University of California, Los Angeles (UCLA)
    • San Diego, California, United States, 92123
      • University of California, San Diego - Rady Children's Hospital
  • Georgia
    • Atlanta, Georgia, United States, 30329
      • Rare Disease Research, LLC
  • Illinois
    • Chicago, Illinois, United States, 60612
      • Rush University Medical Center
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Boston Children's Hospital
  • New York
    • New York, New York, United States, 10021
      • Weill Cornell Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Signed informed consent from parent(s) or legal guardian(s).
• Completed a final study visit in a prior clinical trial with GTX-102. If the subject has an ongoing adverse event, medical monitor approval is required to rollover. The Screening visit must occur within 6 months of the last visit in the prior GTX-102 trial.
• From the time of informed consent through the end of the study and for 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.

Exclusion Criteria:

• Discontinued from prior GTX-102 trial due to treatment-emergent adverse event assessed as related to GTX-102 and where the risk of study participation outweighs the benefits as deemed by the clinical judgment of the Investigator.
• History or evidence of any other medical, neurological, or psychological condition that would expose the subject to an undue risk of a significant AE or interfere with study assessments during the course of the trial as determined by the clinical judgment of the Investigator.
• Known hypersensitivity to GTX-102 or its excipients that, in the judgment of the Investigator, places the subject at increased risk for adverse effects.
• Pregnant or breastfeeding or planning to become pregnant (self or partner) at any time during the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: GTX-102; Participants will receive GTX-102 via intrathecal lumbar puncture (IT LP) on a intrapatient flexible dosing schedule.	Drug: GTX-102; Antisense Oligonucleotide; Other Names: apazunersen

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Frequency, Severity, and Relationship to Investigational Drug of Treatment Emergent Adverse Events (AEs) and Serious Adverse Events (SAEs)	5 Years

Secondary Outcome Measures

Outcome Measure	Time Frame
Change from LTE Month 0 and Pretreatment in the Bayley-4 Raw Score	Month 0, 5 Years

Collaborators and Investigators

• Sponsor: Ultragenyx Pharmaceutical Inc
• Investigators: Study Director: Medical Director, Ultragenyx Pharmaceuticals Inc.

Publications and helpful links

Helpful Links

• Ultragenyx Patient Advocacy Website
• Ultragenyx Angelman Syndrome (AS) Research Study Opportunity
• Ultragenyx Transparency Commitment

Study record dates

Study Major Dates

• Study Start (Actual): July 31, 2024
• Primary Completion (Estimated): February 1, 2029
• Study Completion (Estimated): February 1, 2029

Study Registration Dates

• First Submitted: May 10, 2024
• First Submitted That Met QC Criteria: May 10, 2024
• First Posted (Actual): May 16, 2024

Study Record Updates

• Last Update Posted (Actual): May 6, 2026
• Last Update Submitted That Met QC Criteria: May 4, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Imprinting Disorders; Central Nervous System Diseases; Nervous System Diseases; Genetic Diseases, Inborn; Congenital Abnormalities; Movement Disorders; Abnormalities, Multiple; Chromosome Disorders; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Angelman Syndrome
• Other Study ID Numbers: GTX-102-CL302; 2024-510917-14-00 (Ctis)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No