Ultragenyx Submits Biologics License Application to the U.S. FDA for UX111 AAV Gene Therapy for the Treatment of Sanfilippo Syndrome Type A (MPS IIIA)

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Ultragenyx Pharmaceutical Inc.
Ultragenyx Pharmaceutical Inc.

If approved, UX111 would be the first approved therapy in the U.S. for Sanfilippo Syndrome Type A

NOVATO, Calif., Dec. 19, 2024 (GLOBE NEWSWIRE) -- Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) today announced the submission of a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA or the Agency) seeking accelerated approval for UX111 (ABO-102) AAV gene therapy as a treatment for patients with Sanfilippo syndrome type A (MPS IIIA).

“The path to get a treatment to the point of a BLA filing has been long and perilous for the Sanfilippo community. They have had to watch their children, once thriving, lose their ability to speak and walk, and eventually die, while research programs were shelved due to regulatory and funding hurdles,” said Emil D. Kakkis, M.D., Ph.D., chief executive officer and president of Ultragenyx. “We commend the FDA’s detailed evaluation and acceptance of cerebral spinal fluid (CSF) heparan sulfate (HS) as a well-characterized biomarker to support an accelerated approval pathway for mucopolysaccharidoses (MPS) disorders, including Sanfilippo syndrome. The FDA’s acceptance of CSF HS, which we define as a disease-cause biomarker since it measures the underlying disease, enabled us to file our BLA and may unlock the future accelerated approvals of a host of new therapies for these devastating MPS diseases that affect the brain.”

Earlier this year, Ultragenyx reached agreement with the Agency that CSF HS can be used as a surrogate endpoint for accelerated approval based on the body of data presented by the company, along with a consortium of academics and other industry sponsors at a workshop hosted by the Reagan-Udall Foundation for the FDA in February 2024.

The BLA submission for UX111 is supported by available data, including from the ongoing pivotal Transpher A study, demonstrating treatment with UX111 resulted in rapid and sustained decreased levels of HS in CSF in patients with Sanfilippo syndrome type A, and that sustained reduction in CSF HS exposure over time was correlated with improved long-term cognitive development compared to the decline observed during the same period of time in natural history data. The most frequently reported treatment-related adverse events to date were elevations in liver enzymes, and the majority of these events were mild (Grade 1) or moderate (Grade 2) in severity and all resolved.

About UX111
UX111 is a novel in vivo gene therapy in Phase 1/2/3 development for Sanfilippo syndrome type A (MPS IIIA), a rare fatal lysosomal storage disease with no approved treatment that primarily affects the brain. UX111 is designed to be dosed in a one-time intravenous infusion using a self-complementary AAV9 vector to deliver a functional copy of the SGSH gene to cells. The therapy is designed to address the underlying SGSH enzyme deficiency responsible for abnormal accumulation of heparan sulfate, a glycosaminoglycan, in the brain that results in progressive cell damage and neurodegeneration. The UX111 program has received Regenerative Medicine Advanced Therapy, Fast Track, Rare Pediatric Disease, and Orphan Drug designations in the U.S., and PRIME and Orphan medicinal product designations in the EU.