NOVATO, Calif. - Ultragenyx Pharmaceutical Inc. (NASDAQ: NASDAQ:RARE), a biopharmaceutical company, has announced promising treatment outcomes from its UX111 AAV gene therapy for Sanfilippo syndrome type A (MPS IIIA). Data from the Transpher A study indicated that the therapy led to rapid and sustained reduction of heparan sulfate (HS) in cerebrospinal fluid (CSF), which correlated with improved cognitive development over time.
The pivotal Transpher A study, which included 17 patients, and additional data from a long-term follow-up will be presented at the WORLDSymposium™ 2024, held from February 4-9 in San Diego. The modified intention to treat group (mITT) showed a mean reduction in CSF HS exposure of 63% after treatment with UX111, with a positive rate of cognitive function change in 16 of the 17 patients.
UX111, currently in Phase 1/2 development, is a one-time intravenous infusion therapy using an AAV9 vector to deliver a functional copy of the SGSH gene. This treatment aims to address the underlying enzyme deficiency that causes the accumulation of HS and leads to cell damage and neurodevelopmental decline.
The study's results demonstrated that after receiving the highest dose of UX111 (3x1013 vg/kg), all patients experienced a decrease in CSF-HS within the first month. At 24 months post-treatment, 8 of the 17 patients achieved an average reduction from baseline of 51%. Cognitive function was assessed using Bayley-III cognitive scores, and the correlation between reduced CSF HS exposure and cognitive function was statistically significant.
The majority of treatment-related adverse events were mild or moderate, with only one serious event of increased alanine aminotransferase (ALT) reported, which resolved. This is a known effect of AAV gene therapy.
The Transpher A study has enrolled 28 patients across three dose cohorts at five sites in three countries. Patients from the study are invited to continue in a long-term follow-up for a minimum of five years post-treatment.
Ultragenyx focuses on developing products for rare genetic diseases with high unmet medical needs. The UX111 program has received several designations to facilitate its development, including Regenerative Medicine Advanced Therapy and Fast Track designations in the U.S.
This report is based on a press release statement from Ultragenyx Pharmaceutical Inc.
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