Ultragenyx said its Phase 3 trial of GTX-102 for Angelman syndrome failed to meet its primary efficacy goal, showing no benefit versus sham treatment. The setback is a major inflection point for a biotech that had leaned on early results to build expectations for an eventual path to profitability. Angelman syndrome is a rare neurodevelopmental disorder marked by severe intellectual disability and developmental delays, and GTX-102 is an antisense oligonucleotide therapy designed to modulate disease biology. The failure comes after the company’s earlier signals, which generated hope for families and raised broader interest in cognitive and neurodevelopmental indications. Beyond clinical implications, the result strains Ultragenyx’s investment narrative as investors looked to GTX-102 to complement its portfolio of approved ultra-rare medicines. The company will now need to reassess next steps for the program and resource allocation for remaining assets.