Ultragenyx Wins Approval to Seek FDA Nod for Gene Therapy

Ultragenyx Pharmaceutical has initiated a public stock offering to raise up to $350 million, following a significant update on its drug development pipeline. The company has made headway in its efforts to get the U.S. Food and Drug Administration (FDA) to recognize a specific biomarker as a surrogate endpoint for its Sanfilippo syndrome gene therapy, UX111. This recognition could expedite the approval process, allowing Ultragenyx to file for regulatory approval by the end of the year.

The pivotal trial for UX111, an AAV gene therapy, was already in progress when Ultragenyx acquired global rights from Abeona Therapeutics in 2022. Earlier this year, data reported from the study showed promise, but there was uncertainty about whether the FDA would accept a filing based on the levels of cerebral spinal fluid (CSF) heparan sulfate (HS). This biomarker could potentially serve as a surrogate endpoint for measuring the drug’s efficacy. Ultragenyx presented its case at a Reagan-Udall Foundation event, which included FDA representatives.

Recently, Ultragenyx announced that it had reached an agreement with the FDA regarding the use of CSF HS as a surrogate endpoint for accelerated approval. The company now plans to finalize the details of its filing in an upcoming meeting with the FDA, aiming to apply for approval either late in 2024 or early in 2025.

Ultragenyx intends to base its submission on data from the ongoing pivotal study of UX111. In February, the company reported significant reductions in CSF HS levels within one month of administering the gene therapy. All 17 participants in the modified intention-to-treat group, who suffer from Sanfilippo syndrome (also known as MPS IIIA, a fatal lysosomal storage disease), showed declines in the biomarker.

Additionally, Ultragenyx correlated these reductions in CSF HS with improvements in cognitive function. The company observed a positive rate of change in cognitive abilities, indicating either stability or improvement in 16 out of the 17 patients during the expected window of plateau into decline.

The forthcoming FDA filing will determine whether the agency considers the biomarker results and the initial signs of clinical efficacy sufficient for accelerated approval. While this major hurdle is still ahead, securing the FDA’s agreement to file for approval is a significant milestone in Ultragenyx’s strategy to expand its portfolio of approved drugs swiftly.

Ultragenyx has other ambitious plans in its pipeline. The company aims to apply for approval of its DTX401 gene therapy for glycogen storage disease type Ia next year. Additionally, it is nearing phase 3 data for its setrusumab drug, which is aimed at treating brittle bone disease. Securing approvals for these drugs, along with the resulting revenues and priority review vouchers, is central to Ultragenyx’s strategy to achieve profitability by 2026.

However, bringing UX111 to market will also result in increased expenditures for Ultragenyx. The company is obligated to pay Abeona up to $30 million in commercial milestones tied to regulatory approval. Abeona will also receive tiered royalties of up to 10% on net sales.

In light of these developments, Ultragenyx launched a public offering to raise up to $350 million by selling shares of its common stock. The funds generated will likely support the continued development and potential commercialization of UX111, alongside other promising candidates in its robust pipeline.