U.S.-listed shares of AstraZeneca /zigman2/quotes/200304487/composite AZN +1.93% were down 1.% in premarket trading on Monday after the company said it received an orphan-drug designation for its experimental treatment for transthyretin-mediated amyloidosis, a rare condition that causes heart failure and death within years of diagnosis. The treatment, eplontersen, comes from a development and commercialization deal that AstraZeneca inked with Ionis Pharmaceuticals Inc. /zigman2/quotes/201272020/composite IONS +1.93% in December. AstraZeneca said it aims to file the drug for approval with the Food and Drug Administration by the end of 2022. Ionis shares were down 0.2% in premarket trading. The FDA can give orphan-drug designations to therapies designed to treat diseases or disorders that affect fewer than 20,000 people in the U.S. AstraZeneca's stock is up 1.4% for the year, while Ionis shares have declined 1.8%. The S&P 500 /zigman2/quotes/210599714/realtime SPX -0.58% has tumbled 7.7% year-to-date.