Horizon Therapeutics Plc shares /zigman2/quotes/206690250/composite HZNP -0.07% were halted in premarket trade Friday, ahead of a U.S. Food and Drug Administration advisory committee meeting to discuss a treatment for Thyroid Eye Disease, a serious autoimmune disorder. The FDA's Dermatologic and Ophthalmic Drugs Advisory Committee will meet at 8 a.m. Eastern to discuss teprotumumab, an investigational medicine. The meeting is scheduled to run to 4 p.m. Thyroid Eye Disease often affects patients living with hyperthyroidism or Graves' disease, and can cause long-term damage to eyes, including proptosis, or eye bulging, strabismus, or misalignment of the eyes, and diplopia, or double vision, and in extreme cases can lead to blindness. Teprotumumab has received Priority Review, Orphan Drug and Fast Track and Breakthrough designations from the FDA. Horizon shares have gained 68% in 2019, while the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.54% has gained 26%.