GlaxoSmithKline (GSK) was formed after a merger of Glaxo Wellcome and SmithKline Beecham in 2000. In 2019, GSK was the world's sixth largest pharmaceutical company. It distributes about 65 drugs in the United States. GlaxoSmithKline has more than 80 manufacturing sites including in the U.K., the U.S., and Asia.