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Ultragenyx Announces U.S. FDA Acceptance of BLA Resubmission for UX111 AAV Gene Therapy to Treat Sanfilippo Syndrome Type A (MPS IIIA)
If approved, UX111 will be the first approved therapy for the treatment of Sanfilippo syndrome Type A, a rare disease affecting young children that leads to
About this update from Ultragenyx Pharmaceutical Inc.
[{"type":"text","content":"If approved, UX111 will be the first approved therapy for the treatment of Sanfilippo syndrome Type A, a rare disease affecting young children that leads to progressive, irreversible neurodegeneration and early death PDUFA action date set for September 19, 2026 NOVATO, Calif., April 02, 2026 (GLOBE NEWSWIRE) -- Ultragenyx Pharmaceutical Inc. (NASDAQ: RARE) today announced the U.S. Food and Drug Administration (FDA or the Agency) has accepted for review the resubmitted Biologics License Application (BLA) seeking accelerated approval for UX111 (rebisufligene etisparvovec) AAV9 gene therapy as a treatment for patients with Sanfilippo syndrome Type A (MPS IIIA). The FDA set a Prescription Drug User Fee Act (PDUFA) action date of September 19, 2026. “The FDA’s acceptance of the BLA for UX111 brings us closer to the possibility of a first-ever therapy for Sanfilippo syndrome Type A—a milestone that we recognize cannot come soon enough for families facing this devastating diagnosis,” said Emil D. Kakkis, M.D., Ph.D., chief executive officer and president of Ultragenyx. “We appreciate the FDA’s prompt acceptance of the resubmission and look forward to working with the Agency throughout its review in order to bring this treatment option to the Sanfilippo syndrome community as quickly as possible.” During its prior late-cycle review, the FDA acknowledged that the neurodevelopmental outcome data are robust and that the biomarker data provide additional supportive evidence. The updated long-term clinical data included in the BLA and presented at WORLDSymposium™ 2026 represent up to 8 years of follow-up and show further clinical improvement relative to the decline observed in natural history, and a durable treatment effect across clinical evaluations and multiple biomarkers, while maintaining an acceptable safety profile. The FDA granted the UX111 BLA Priority Review in February 2025. If approved, UX111 will be manufactured entirely within the U.S., at Andelyn Biosciences in Columbus, Ohio and the Ultragenyx gene therapy manufacturing facility in Bedford, Massachusetts. About UX111 (rebisufligene etisparvovec)UX111 (rebisufligene etisparvovec) is a novel in vivo AAV9 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 b...