Ultragenyx's Angelman syndrome drug fails in Phase 3 trial, showing no benefit

Ultragenyx announced that its experimental therapy GTX-102 for Angelman syndrome did not demonstrate any benefit compared with a sham control in a large Phase 3 trial.

The drug had previously shown promising results in early-stage studies, which had raised hopes among families and patient advocates for a treatment that could improve cognition and development.

The negative outcome is a blow to Ultragenyx, whose portfolio consists mainly of ultra-rare approved medicines, and investors had counted on the Angelman program to move the company toward profitability.

The result highlights the ongoing challenges of developing effective therapies for severe neurodevelopmental disorders.