Alexion Pharmaceuticals Inc. is an American pharmaceutical company best known for its development of Soliris, a drug used to treat the rare disorders atypical hemolytic uremic syndrome (aHUS) and paroxysmal nocturnal hemoglobinuria (PNH). The company is also involved in immune system research related to autoimmune diseases. It employs around 2,400 people worldwide. In February 2016, the company held the dedication ceremony for its new headquarters in New Haven, Connecticut, not far from the company's starting point in the same city.
In September 2017, Alexion announced it would be moving its headquarters to Boston, Massachusetts, in mid-2018.
In December 2020, the company was acquired by AstraZeneca for a reported $39 billion.
Alexion Pharmaceuticals was founded in 1992 at Science Park in New Haven, Connecticut by Steven Squinto and Leonard Bell. Bell served as the company's CEO until 2015. In 2000, Alexion moved its headquarters from New Haven to Cheshire, Connecticut. Alexion moved back to New Haven following the completion of New Haven's Downtown Crossing project in December 2015.
Since 2006, Alexion has been a supporter of healthcare research and quality studies at Duke University for aspirin and Clopidogrel (trade name Plavix).
Alexion received U.S. Food and Drug Administration (FDA) approval for Soliris in 2007. It was initially approved to treat paroxysmal nocturnal hemoglobinuria, a rare blood disorder. In 2010, there was an outbreak of hemolytic-uremic syndrome caused by Enterohaemorrhagic Escherichia coli (EHEC) in Germany. Soliris was considered a treatment option because of its effectiveness in treating Atypical hemolytic uremic syndrome, an illness similar to the one caused by the EHEC infection.
In April 2011, Alexion was added to the NASDAQ-100, a group composed of the 100 largest non-financial stocks traded on the NASDAQ; with a market value of US$8.5 billion it replaced Genzyme Corporation.
In April 2015, Bell was replaced as CEO by David Hallal. In 2016, the company became a member of the Pharmaceutical Research and Manufacturers of America (PhRMA).
In December 2016, Alexion's board of directors announced new leadership. David Brennan, a current board member, became interim CEO. David Anderson, formerly the CFO of Honeywell, was appointed CFO, replacing Vikas Sinha. In March 2017, Alexion named Ludwig N. Hantson as its new CEO.
In September 2017, Alexion announced that it would be closing its Smithfield, RI manufacturing facility.