A Phase 3 interventional study of No Investigational Product and Adjuvant Immunomodulatory (IM) Therapy in Mucopolysaccharidosis IIIA, MPS IIIA and Sanfilippo Syndrome, sponsored by Ultragenyx Pharmaceutical Inc. Enrolling by invitation at 4 sites in 3 countries. Per ClinicalTrials.gov, last updated 2026-07-17.
Sponsored by Ultragenyx Pharmaceutical Inc · Phase 3, Interventional, and Other
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Among 13 studies in Mucopolysaccharidosis III with a site in Spain — 2 open to participants now, 3 under way, 2 of them phase 3. Mucopolysaccharidosis III · Spain.
Among the 13 studies in Mucopolysaccharidosis III with a site in Spain, this one is the only one that started in 2020, is the only one in phase 3, and was the 13th registered.
58 studies on the registry are indexed under Mucopolysaccharidosis III; 16 are open to participants now.
Browse Mucopolysaccharidosis III studies →2 of the 13 studies in Mucopolysaccharidosis III with a site in Spain are open now. Recruiting first, the newest first:
Ultragenyx Pharmaceutical Inc · Sites in Spain, United States, Australia
A study can be open while its sites in Spain have not opened yet or have stopped. Only those recruiting at a site in Spain →
Of the 8 Mucopolysaccharidosis III studies recruiting now, 5 set no upper age limit and 1 stops at 75 or younger; 7 take children under 18; none take healthy volunteers.
This study: all sexes · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
13 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 4 · Phase 2 8 · Phase 3 2
First in 2013; this study’s year is marked. 1 started in 2020.
This study's planned enrollment of 41 is above the median of 12 across 33 interventional studies indexed under Mucopolysaccharidosis III.
Median enrollment 20 across the 9 interventional studies, 30 across the 4 observational. Of the 9 that completed or were terminated, 4 (44%) have results posted.
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13 of 13 have an industry lead sponsor. The 5 most frequent:
Ultragenyx Pharmaceutical Inc is the lead sponsor of 63 studies on the registry; 8 are open to participants now.
Of its 16 completed or terminated interventional studies of FDA-regulated products, 12 (75%) have results posted.
Ultragenyx Pharmaceutical Inc has 4 studies filed under Mucopolysaccharidosis III — fewer than ten, so there is no comparison to draw.
1 of the studies in Mucopolysaccharidosis III with a site in Spain that are under way reach primary completion within a year, 1 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT04360265Phase 3Ultragenyx Pharmaceutical IncFollow-up Study of AAV-Mediated Gene Transfer (UX111; Previously Known as ABO-102) for MPS Type IIIA | 2027-08 |
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Among the 13 studies in Mucopolysaccharidosis III with a site in Spain, from their registry updates:
Nothing recorded among them since 2026-09-25.
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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).
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.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Other: No Investigational Product · Drug: Adjuvant Immunomodulatory (IM) Therapy
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.
Other: No Investigational Product
No investigational product will be administered in this follow-up trial.
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.
Number of Participants with Treatment-Emergent Adverse Events (TEAEs) and Treatment-Emergent Serious Adverse Events (SAEs)
Time frame: Up to Year 5
Bayley Scales of Infant and Toddler Development - Third Edition (BSITD-III) Cognitive Raw Score Over Time
Time frame: Up to Year 5
Cerebrospinal Fluid (CSF) Heparin Sulfate (HS) (Disaccharide) Exposure
Time frame: Baseline, Up to Month 36
Percent Change From Baseline in Prior Trial in CSF HS
Time frame: Baseline, Up to Month 36
BSITD-III Receptive Communication Raw Score Over Time
Time frame: Up to Year 5
BSITD-III Expressive Communication Raw Score Over Time
Time frame: Up to Year 5
Annualized Percentage Change from Baseline in Prior Trial in Total Cortical Volume
Time frame: Baseline, Up to Month 36
Survival
Time frame: Up to Year 5
Plan to share: No
Started Sep 2020 (actual). Primary completion is estimated for Aug 2027, 83 months after the start.
How these figures are worked out, and which studies are left out of them.
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No contact was published for this record. The registry link below has the sponsor’s details.
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Ultragenyx Pharmaceutical Inc →