AbbVie Inc. and Amgen Inc. have reached a settlement requiring Amgen to wait until 2023 to start selling its biosimilar version of AbbVie’s adalimumab (Humira) in the United States. The deal could give AbbVie an unusually long 20-year U.S. monopoly on sales of the drug, which costs more than $57,000 annually per patient. AbbVie secured more than 100 patents to protect its sales of adalimumab, which treats a range of conditions including rheumatoid arthritis and gut disorders. The companies’ dispute began when Amgen received FDA approval to start selling a copy of adalimumab in the United States in September 2016. AbbVie sued Amgen in federal court, seeking to block the copy and alleging it violated many patents. Under the new settlement, Amgen said AbbVie will grant patent licenses for the sale of its biosimilar, and the companies have agreed to dismiss all pending litigation. Amgen plans to launch the drug in Europe in October 16, 2018, and in the United States on January 31, 2023.