Follow-up Study of AAV-Mediated Gene Transfer (UX111; Previously Known as ABO-102) for MPS Type IIIA

Phase 3

• Conditions: MPS IIIA; Mucopolysaccharidosis IIIA; Sanfilippo Syndrome; Sanfilippo A
• Interventions: Other: No Investigational Product; Drug: Adjuvant Immunomodulatory (IM) Therapy

• Registration Number: NCT04360265
• Lead Sponsor: Ultragenyx Pharmaceutical Inc

Brief Summary

The main objective of this study is to evaluate the safety/tolerability and efficacy of UX111 (previously known as ABO-102) in participants with Mucopolysaccharidosis IIIA (MPS IIIA).

Detailed Description

This is a multicenter, long-term follow-up study of patients with MPS IIIA who have participated in a prior clinical trial involving the administration of UX111 (NCT02716246 and NCT04088734). No investigational product will be provided. At approved sites adjuvant immunomodulatory (IM) therapy may be administered to selected participants. The Principal Investigator and/or caregiver, in consultation with the medical monitor, will determine whether to initiate adjuvant IM therapy. Not all participants may receive IM therapy.

This study was previously posted by Abeona Therapeutics, Inc and was transferred to Ultragenyx in August 2022.

Study Timeline

• Study First Submitted: 2020-04-20
• Study First Submitted QC: 2020-04-21
• Study First Posted: 2020-04-24
• Study Start: 2020-09-28
• Status Verified: 2025-01
• Last Update Submitted: 2025-04-09
• Last Update Posted: 2025-04-13
• Primary Completion: 2027-08
• Study Completion: 2027-08

Recruitment & Eligibility

• Status: ENROLLING_BY_INVITATION
• Sex: All
• Target Recruitment: 41

Inclusion Criteria

• Participants that have participated in a prior clinical trial in which they received UX111
• Parent(s)/legal guardian(s) of participant willing and able to complete the informed consent process and comply with study procedures and visit schedule

Exclusion Criteria

• Planned or current participation in another clinical trial that may confound the safety or efficacy evaluation of UX111 during this study
• Any other situation or medical condition that precludes the participant from undergoing procedures required in this study

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Cohort A	No Investigational Product	Participants who have participated in a prior clinical trial involving the administration of UX111 (rebisufligene etisparvovec) and are able to comply with onsite scheduled visits and assessments. Select participants may receive adjuvant IM therapy.
Cohort A	Adjuvant Immunomodulatory (IM) Therapy	Participants who have participated in a prior clinical trial involving the administration of UX111 (rebisufligene etisparvovec) and are able to comply with onsite scheduled visits and assessments. Select participants may receive adjuvant IM therapy.
Cohort B	No Investigational Product	Participants who have participated in a prior clinical trial involving the administration of UX111 (rebisufligene etisparvovec) and who cannot participate in Cohort A. Participants will partake in a reduced number of assessments, performed either onsite or at home via a combination of telehealth and home healthcare visits.

Primary Outcome Measures

Name	Time	Method
Number of Participants with Treatment-Emergent Adverse Events (TEAEs) and Treatment-Emergent Serious Adverse Events (SAEs)	Up to Year 5
Bayley Scales of Infant and Toddler Development - Third Edition (BSITD-III) Cognitive Raw Score Over Time	Up to Year 5

Secondary Outcome Measures

Name	Time	Method
BSITD-III Receptive Communication Raw Score Over Time	Up to Year 5
Survival	Up to Year 5
BSITD-III Expressive Communication Raw Score Over Time	Up to Year 5
Annualized Percentage Change from Baseline in Prior Trial in Total Cortical Volume	Baseline, Up to Month 36
Percent Change From Baseline in Prior Trial in CSF HS	Baseline, Up to Month 36
Cerebrospinal Fluid (CSF) Heparin Sulfate (HS) (Disaccharide) Exposure	Baseline, Up to Month 36

Trial Locations

Locations (4)

Vall d'Hebron Barcelona Campus; 🇪🇸 Barcelona, Spain

Nationwide Children's Hospital; 🇺🇸 Columbus, Ohio, United States

Women's and Children's Hospital; 🇦🇺 North Adelaide, South Australia, Australia

Hospital Clínico Universitario de Santiago; 🇪🇸 Santiago De Compostela, Spain