Ultragenyx's Angelman Syndrome Drug Fails to Meet Endpoints in Phase 3 Trial

Ultragenyx Pharmaceutical Inc. announced that its Phase 3 Aspire study for apazunersen (GTX-102), an investigational drug for Angelman syndrome, did not achieve its primary endpoint of change from baseline in Bayley-4 cognitive raw score, nor the key secondary endpoint of net response in the multidomain responder index. The safety profile observed in the trial was consistent with earlier Phase 1/2 studies. The company plans to evaluate the future of the apazunersen program and implement significant expense reductions.