Dive Brief:
- Ultragenyx on Wednesday won Food and Drug Administration approval to sell the first treatment for patients with a rare genetic condition known as glycogen storage disease type Ia.
- Patients with GSDIa have a genetic mutation leaving them without a critical enzyme that helps the body stabilize blood sugar levels between meals. Ultragenyx’s one-time therapy, known as Glenglycos, is designed to deliver a functional gene to the liver, aiming to restore the enzyme and treat the potentially life-threating metabolic imbalance.
- With the FDA decision, Ultragenyx now has five approved products and its first marketable gene therapy. Glenglycos will have a per-patient wholesale acquisition cost of $2.7 million, company officials told investors and analysts on a conference call. They plan to have the therapy available within 30 to 60 days at specialized treatment centers.
Dive Insight:
Analysts don’t expect Glenglycos to be a blockbuster product, but the approval is a significant win for a company that has suffered a number of setbacks in recent years. It also comes with a priority review voucher that Ultragenyx plans to sell. These regulatory fast passes are in great demand; this year, three vouchers sold for $180 million, $195 million and $200 million, respectively.
The sale will support Ultragenyx’s “path to profitability,” Chief Financial Officer Howard Horn said on a Wednesday conference call. Company officials expect that to happen in 2027, bolstered by the approval of Glenglycos and potentially another gene therapy known as UX111 that has a Sept. 19 deadline for FDA action.
UX111, designed to treat a rare neurodegenerative disorder called Sanfilippo syndrome Type A, has had a rocky regulatory path so far. The FDA rejected the therapy in 2025 because of manufacturing concerns, then earlier this year said a response from the company was incomplete. Ultragenyx resubmitted its application, and announced in April that the FDA accepted the submission.
Approval of that therapy could come with another valuable priority review voucher, William Blair analyst Sami Corwin wrote in a note to clients. But she believes investors are most focused on the results of a pivotal trial due in September or October for GTX-102, a treatment for another rare disease known as Angelman syndrome. That “will be a significant catalyst for the stock,” Corwin wrote.
Corwin expects peak sales of Glenglycos to reach $362 million. The therapy was cleared for market through the FDA’s accelerated approval process, which means that the company will have to provider longer-term data showing a clinical benefit. Company officials said they plan to monitor patients along with a control group for 10 years, although the FDA is only requiring two more years of data for a full approval.
To prevent potentially life-threating episodes of hypoglycemia, patients with GSDIa typically ingest a slurry of cornstarch every four hours, day or night. It’s a demanding regimen that’s combined with dietary restrictions and careful monitoring. The initial FDA approval was based on data showing the therapy could help patients reduce their cornstarch intake.
The regulatory clearance “is a great milestone in using a gene therapy to treat this disease and improve the quality of life for people with this condition,” Karim Mikhail, the acting director of the FDA’s biologics center, said in a statement.
