Ultragenyx Shares Drop As Muscle-disease Drug Study Fails

Ultragenyx Pharmaceutical Inc. shares fell in the extended session Tuesday after the biotech company said a late-stage clinical trial for its severe muscle disease treatment did not reach its goals. Shares of Ultragenyx dropped 10% to $52.96 after hours following a brief halt. The company said its Phase 3 clinical trial for extended-release aceneuramic acid did not significantly improve strength in patients with GNE Myopathy, a rare disease where muscles cannot modify proteins and fats because of an enzyme deficiency.