Ultragenyx rises as gene therapy shows long‑term benefit in rare childhood brain disorder

Ultragenyx Pharmaceutical

03/02/2026 13:44

** Shares of drugmaker Ultragenyx RARE.O rise 4% to $25.75 in premarket trading

** Co says its experimental gene therapy helps children with Sanfilippo syndrome Type A - a rare disorder that rapidly damages the brain - retain key abilities for more than eight years

** Sanfilippo Type A happens when the body cannot break down certain substances, leading to severe brain decline; most children die in their teens, according to co

** Co says treated children kept skills like walking, communicating and eating independently, while most untreated kids lose these abilities early

** Co's therapy, UX111, given as one-time infusion; most common side effect was temporary liver enzyme increase

** RARE resubmits FDA application for accelerated approval; expects decision in Q3 2026, co says

** Shares down ~45% in 2025

(Reporting by Sahil Pandey in Bengaluru)

((Sahil.Pandey@thomsonreuters.com))