Recent Updates
Recently added Catalysts

UX111

Phase 2

MPS IIIA | Monoclonal antibody | Rare Disease |Ultragenyx Pharmaceutical Inc.|Last Updated: Aug 21, 2026

Success Probability

Subscribe to view

Market & Valuation

Subscribe to view

Trial Design

CONTROLLEDDMC
Total Trials1
Total Enrollment36

FDA Designations

RMATFAST_TRACKORPHAN_DRUGRARE_PEDIATRIC_DISEASEACCELERATED_APPROVAL

Clinical trial landscape

UX111 · 1 trial · 4 indications

Phase 2 1
NCT02716246Phase I/II/III Gene Transfer Clinical Trial of scAAV9.U1a.hSGSHMPS IIIA
RECRUITING36 Analytics
PHASE2RECRUITING
Phase I/II/III Gene Transfer Clinical Trial of scAAV9.U1a.hSGSH
MPS IIIAUnlock trial analytics

Study Endpoints

Primary Endpoints

Cerebrospinal Fluid (CSF) Heparan Sulfate (HS) (Disaccharide) Exposure
Up to Month 24 Visit

Exposure is defined as the time-normalized area under the curve (AUC) of the percentage reduction from baseline.

Secondary Endpoints

Bayley Scales of Infant and Toddler Development-Third Edition (BSITD-III) Cognitive Raw Score Over Time
Up to Month 24 Visit
CSF Ganglioside Type 2 (GM2) Exposure
Up to Month 24 Visit
CSF Ganglioside Type 3 (GM3) Exposure
Up to Month 24 Visit
Unlock Study Endpoints

Study Design & Arms

AllocationNON_RANDOMIZED
MaskingNONE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Cohort 1 Low DoseEXPERIMENTALDose of 0.5 X 10\^13 vg/kg
Cohort 2 Mid DoseEXPERIMENTALDose of 1 X 10\^13 vg/kg
Cohort 3 High DoseEXPERIMENTALDose of 3 X 10\^13 vg/kg
Cohort 4 High Dose (Spain Only)EXPERIMENTALDose of 3 X 10\^13 vg/kg

Interventions

NameTypeDescription
UX111BIOLOGICALSelf-complementary adeno-associated virus serotype 9 carrying the human SGSH gene under the control of a U1a promoter (scAAV9.U1a.hSGSH) will be delivered one time through a venous catheter inserted into a peripheral limb vein.
Prophylactic Immunomodulatory (IM) TherapyDRUG -
Optimized Prophylactic IM TherapyDRUG -
Adjuvant IM TherapyDRUGThe Principal Investigator and/or caregiver, in consultation with the medical monitor, will determine whether to initiate adjuvant IM therapy. Not all participants may receive adjuvant IM therapy.
Unlock Study Design Details

Eligibility Criteria

SexALL
Healthy VolunteersNo
Study Sites5

Inclusion Criteria: * Diagnosis of MPS IIIA confirmed by the following methods: * No detectable or significantly reduced SGSH enzyme activity by leukocyte assay, and * Genomic DNA analysis demonstrating homozygous or compound heterozygous mutations in the SGSH gene (based upon review of docume...

Countries:United StatesAustraliaSpain
Unlock Eligibility Criteria

Recent Changes (Last 90 Days)

LOWAug 21, 2026NCT02716246lastUpdatePostDate: changed
LOWAug 21, 2026NCT02716246lastUpdatePostDate: changed
LOWJul 17, 2026NCT02716246lastUpdatePostDate: changed
LOWJul 17, 2026NCT02716246lastUpdatePostDate: changed
MEDIUMJun 11, 2026NCT02716246primaryCompletionDate: changed
MEDIUMJun 11, 2026NCT02716246primaryCompletionDate: changed

Frequently asked questions about UX111

What is UX111 used for in MPS IIIA?

UX111 is an investigational gene therapy being developed for the treatment of MPS IIIA, also known as Sanfilippo syndrome type A. It is designed to address the underlying genetic cause of this rare disease. The drug is currently in Phase 2 clinical development and has not yet been approved by regulatory authorities.

What does UX111 target?

UX111 is a gene therapy that delivers a functional copy of the SGSH gene using an adeno-associated viral vector. The SGSH gene provides instructions for producing the enzyme N-sulfoglucosamine sulfohydrolase, which is deficient in patients with MPS IIIA. This enzyme is essential for breaking down certain complex carbohydrates in the body.

Who makes UX111?

UX111 is being developed by Ultragenyx Pharmaceutical Inc., a biopharmaceutical company traded on the NASDAQ under the ticker symbol RARE. Ultragenyx focuses on developing therapies for rare and ultrarare diseases. The company is conducting clinical trials to evaluate the safety and efficacy of UX111 in patients with MPS IIIA.

What phase is UX111 in?

UX111 is currently in Phase 2 clinical development. It is being evaluated in an ongoing Phase I/II/III gene transfer clinical trial. The drug has received several FDA designations, including Regenerative Medicine Advanced Therapy (RMAT), Fast Track, Orphan Drug, Rare Pediatric Disease, and Accelerated Approval, reflecting its potential to address a serious unmet medical need.

What clinical trials is UX111 in?

UX111 is being studied in a single clinical trial registered as NCT02716246, titled 'Phase I/II/III Gene Transfer Clinical Trial of scAAV9.U1a.hSGSH'. This trial is currently recruiting participants with MPS IIIA, Sanfilippo syndrome, and related conditions. The study is enrolling up to 36 patients across the United States, Australia, and Spain.

Is UX111 the same as scAAV9.U1a.hSGSH?

Yes, UX111 is also known as scAAV9.U1a.hSGSH, which is the name used in the clinical trial title. This designation refers to the specific gene therapy construct being tested. The trial NCT02716246 is evaluating this therapy in patients with MPS IIIA and Sanfilippo syndrome.