Investors.com will undergo scheduled maintenance from 10:00 PM ET to 2:00 AM ET and some features may be unavailable. We apologize for any inconvenience.
Ultragenyx stock crashed Thursday, losing almost half its value, after its experimental Angelman treatment failed in final-phase testing. Angelman syndrome causes developmental delays, balance problems and speech impairment. In the Phase 3 test, patients treats with Ultragenyx Pharmaceuticals' (RARE) drug, apazunersen, didn't show improvements in cognition. They also missed on a second metric, a composite score examining whether patients responded…
