UX111 is an investigational in vivo AAV9 gene therapy candidate for Sanfilippo syndrome type A (MPS IIIA). It is designed as a one-time intravenous infusion delivering a functional SGSH gene copy to address the underlying enzyme deficiency and reduce heparan sulfate accumulation. Ultragenyx resubmitted its BLA in January 2026 and regulatory review is ongoing.
Ultragenyx Pharmaceutical confronts multiple shareholder class action lawsuits over Phase III trial disclosures while reporting positive UX111 gene therapy data and implementing a 10% workforce reduction.
Ultragenyx Pharmaceutical announced positive long-term clinical data for UX111 gene therapy for Sanfilippo syndrome Type A, with up to 8.5 years of follow-up showing sustained biomarker reductions and functional improvements. The company resubmitted its BLA to the FDA in January 2026.
Ultragenyx Pharmaceutical received an Incomplete Response Letter from the FDA for its UX111 gene therapy resubmission for Sanfilippo syndrome type A, requesting additional documentation. The company announced a 10% workforce reduction and expects profitability by 2027.
Ultragenyx will lay off 130 employees as part of restructuring aimed at profitability by 2027. The FDA rejected the company's gene therapy application for Sanfilippo syndrome due to manufacturing concerns.
Ultragenyx reported Q4 2025 revenues of $207 million, up 25% year-over-year, while announcing a 10% workforce reduction and resubmission of its UX111 gene therapy application following positive long-term clinical data.
| NCT ID | Title | Status | Phase |
|---|---|---|---|
| NCT02716246 |
Phase I/II/III Gene Transfer Clinical Trial of scAAV9.U1a.hSGSH |
RECRUITING | PHASE2/PHASE3 |
