Ultragenyx Reports Positive Long-Term Data for UX111 Gene Therapy, Bolstering BLA Resubmission
RARE sits 36% above its 52-week low of $18.41.
Summary
Ultragenyx reported strong long-term clinical data for its UX111 gene therapy for Sanfilippo syndrome type A, showing significant functional and biomarker improvements, which were included in its recently resubmitted BLA to the FDA.
Key Events · Product Development and Regulatory · RARE
-
Positive Long-Term Clinical Data for UX111
New data from clinical studies evaluating UX111 gene therapy for Sanfilippo syndrome type A (MPS IIIA) demonstrated substantial and durable biomarker improvements and meaningful functional benefits compared to natural history.
-
Significant Functional Improvements Observed
Children under two years or with earlier-stage disease showed a +23.2 point treatment effect in Bayley-III cognitive raw scores. Improvements were also noted in receptive and expressive communication, and fine and gross motor skills.
-
Functional Skill Retention in Later-Stage Children
Patients with more advanced disease showed retention of functional abilities (communication, ambulation, self-feeding) that exceed typical decline patterns in untreated children.
-
Favorable Safety Profile Confirmed
UX111 was generally well-tolerated across all doses, with treatment-related adverse events being mostly mild or moderate and resolving spontaneously.
Analysis · RARE · Life Sciences
Ultragenyx Pharmaceutical Inc. announced compelling long-term clinical data for its UX111 gene therapy, which targets Sanfilippo syndrome type A (MPS IIIA), a severe neurodegenerative disorder. The data demonstrates significant and durable improvements in biomarkers and functional abilities across various age groups and disease stages, compared to natural history. This positive outcome, coupled with a favorable safety profile, strengthens the company's Biologics License Application (BLA) for UX111, which was recently resubmitted to the FDA. The anticipated PDUFA date in the third quarter of 2026 marks a critical milestone for potential accelerated approval, offering hope for patients with this fatal condition.
How filings like this one have moved
In the 30 days to Sep 14, 2026, 35.8% of the 1045 measured filings Wiseek scored 8 moved their stock by 5% or more by the next session's close. The median move was -0.43%. These are measured outcomes after filings of this importance, not a forecast for this one.
Measured one observation per ticker per day, after exclusions. Current figures: Filing Impact Tracker · open dataset
At the time of this filing, RARE was trading at $25.00 on NASDAQ in the Life Sciences sector, with a market capitalization of approximately $2.4B. The 52-week trading range was $18.41 to $46.50. This filing was assessed with positive market sentiment and an importance score of 8 out of 10.