Ultragenyx's Angelman syndrome drug fails Phase 3 trial, halting development

Ultragenyx reported that its experimental antisense oligonucleotide designed for Angelman syndrome did not meet primary endpoints in a Phase 3 study.

The trial, which enrolled patients with the rare neurodevelopmental disorder, failed to demonstrate a statistically significant improvement in the key efficacy measures compared with placebo.

The company said the results represent a setback for both the firm and patients hoping for a disease-modifying therapy, and it will reassess its development strategy.

Analysts noted that the negative outcome could impact Ultragenyx's pipeline outlook and may affect investor sentiment pending further updates.