RARE ▼ -41.8% - Ultragenyx Pharmaceutical Inc. $RARE - Ultragenyx Announces Phase 3 Aspire results in Angelman Syndrome Ultragenyx Pharmaceutical shares fell 41.8% following the announcement of Phase 3 Aspire trial results in Angelman Syndrome, suggesting the data disappointed investors or missed key efficacy or safety endpoints. The magnitude of the decline indicates the market viewed the outcome as materially negative for the company's pipeline prospects in this indication. 02-SEP-2026 04:01 PM ET