Britain's AstraZeneca has decided to buy the U.S. drugmaker Alexion Pharmaceuticals over a deal worth $39 billion, it is being the company's largest ever deal. The deal diversifies the company away from its fast-growing cancer business in a bet on rare-disease and immunology drugs. The deal comes in a week that AstraZeneca informed that the company was conducting further research to confirm whether its COVID-19 vaccine could be 90% effective, potentially slowing its rollout. The company's rival shot from Pfizer was launched in Britain and approved for use in the United States. Astrazeneca said on Saturday that Alexion shareholders would receive $60 in cash and about $115 worth of equity per share either in AstraZeneca's UK-traded ordinary shares or in dollar-denominated American Depositary Shares. Based on a reference average ADR price of $54.14, that implies a total price of $175 per share. Alexion shares closed at around $121 per share on Friday. Of the various products, Alexion's best-selling drug is Soliris, used against a range of rare immune-disorders including paroxysmal nocturnal hemoglobinuria (PNH). AstraZeneca expects significant growth from introducing the target's rare-disease treatments to China and other emerging markets. An official statement said the boards of both companies had approved the deal, and is expected to close in the third quarter of 2021. Oxford-Astrazeneca Corona vaccine may arrive in early 2021 India largest buyer of Covid 19, 1.6 billion doses to inoculate 800 million people Norway to use three vaccines to battle Covid 19