Alexion Pharmaceuticals
Alexion Pharmaceuticals is a rare-disease biopharmaceutical company operating as a subsidiary of AstraZeneca.
Last updated August 31, 2026
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Overview
Alexion Pharmaceuticals is a biopharmaceutical company focused on medicines for rare and life-threatening diseases. Founded in 1992 by Steven Squinto and Leonard Bell in New Haven, Connecticut, the company built its identity around complement biology, immunology, and the development of treatments for conditions with small patient populations and substantial unmet medical need. Its commercial portfolio has included medicines for paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome, hypophosphatasia, lysosomal acid lipase deficiency, and life-threatening bleeding associated with certain anticoagulants. The company’s defining product has been eculizumab, marketed as Soliris. Approved by the U.S. Food and Drug Administration in 2007 for paroxysmal nocturnal hemoglobinuria, Soliris became a foundational treatment for disorders involving uncontrolled activation of the complement system. Its indications subsequently included atypical hemolytic uremic syndrome. The product’s high clinical value, rarity of the diseases treated, and pricing structure made Alexion one of the best-known examples of the commercial orphan-drug model. Public descriptions of the company have noted that annual treatment costs for some patients could reach exceptionally high levels, contributing to continuing debate over access, reimbursement, and pricing of rare-disease medicines. Alexion expanded beyond Soliris through internal development and acquisitions. Enobia Pharma brought asfotase alfa, later marketed as Strensiq, for hypophosphatasia. The acquisition of Synageva added sebelipase alfa, marketed as Kanuma, for lysosomal acid lipase deficiency. Later transactions added programs and products in immunology, hematology, neurology, and critical care, including andexanet alfa, marketed as Andexxa, a reversal agent intended to help stop life-threatening or uncontrolled bleeding in patients taking rivaroxaban or apixaban. Alexion also developed ravulizumab, marketed as Ultomiris, a longer-acting complement inhibitor that extended the company’s franchise beyond Soliris. Corporate development was a major part of Alexion’s history. The company acquired Proliferon in 2000 and renamed it Alexion Antibody Technologies. It bought Enobia in 2011, Synageva in 2015, Wilson Therapeutics and Syntimmune in 2018, Achillion Pharmaceuticals in 2020, and Portola Pharmaceuticals later in 2020. These transactions broadened its research capabilities, rare-disease pipeline, and commercial portfolio. Alexion also entered a collaboration with Moderna in 2014 involving options for rare-disease programs based on messenger-RNA technology, although the program was discontinued in 2017 after preclinical work did not support further development. The company experienced significant leadership and organizational changes during the 2010s. Leonard Bell was replaced as chief executive by David Hallal in 2015; David Brennan served as interim chief executive in 2016, followed by Ludwig N. Hantson in 2017. In 2017 Alexion announced a workforce reduction, the closure of its Smithfield, Rhode Island manufacturing facility, and a headquarters move to Boston. In 2020 it agreed to pay more than $21 million to resolve allegations concerning improper payments involving officials in Turkey and Russia. AstraZeneca agreed to acquire Alexion in 2020, completing the transaction in July 2021 for approximately $39 billion. Alexion now functions as AstraZeneca’s rare-disease business, retaining a distinct scientific and commercial identity within the larger pharmaceutical group.
History
Alexion Pharmaceuticals was established in 1992 at Science Park in New Haven, Connecticut, by Steven Squinto and Leonard Bell. Bell was a physician associated with Yale New Haven Hospital and an assistant professor at Yale School of Medicine. From its beginning, Alexion concentrated on antibody technologies and diseases involving dysregulated immune responses, an orientation that later developed into a leading commercial focus on complement inhibition and rare diseases. In 2000, Alexion moved its headquarters from New Haven to Cheshire, Connecticut, and acquired Proliferon, a development-stage biopharmaceutical company, for stock valued at approximately $41 million. Proliferon was renamed Alexion Antibody Technologies, reinforcing the company’s interest in antibody discovery and development. Alexion’s major commercial breakthrough came in 2007, when the FDA approved Soliris, or eculizumab, for paroxysmal nocturnal hemoglobinuria. The medicine targeted terminal complement activity and addressed a condition for which effective treatment options had been limited. Its use was later expanded to atypical hemolytic uremic syndrome. The company grew through a combination of product development, licensing, partnerships, and acquisitions. In 2011 it acquired Montreal-based Enobia Pharma for approximately $1.08 billion, obtaining asfotase alfa. The product was developed for hypophosphatasia and later approved as Strensiq. In 2014 Alexion paid Moderna $100 million for options relating to ten potential rare-disease products using Moderna’s messenger-RNA technology. The program was abandoned in 2017 after animal studies did not indicate that the proposed treatment approach could be made sufficiently safe for human use. In 2015 Alexion acquired Synageva in a transaction valued at approximately $8.4 billion in cash and stock. Synageva added sebelipase alfa, later marketed as Kanuma, for lysosomal acid lipase deficiency. That year also brought a leadership transition: David Hallal replaced Bell as chief executive, and the FDA approved Strensiq for hypophosphatasia. Alexion joined the Pharmaceutical Research and Manufacturers of America in 2016. During the same period, it moved its headquarters back to New Haven after completion of the Downtown Crossing project. David Brennan became interim chief executive in December 2016, while David Anderson, formerly of Honeywell, became chief financial officer in place of Vikas Sinha. Ludwig N. Hantson was appointed chief executive in March 2017. Alexion announced a major restructuring in September 2017. The plan included a workforce reduction of approximately 20 percent, the closure of its manufacturing facility in Smithfield, Rhode Island, and relocation of the corporate headquarters to Boston in 2018. The company continued to expand its rare-disease pipeline through acquisitions. In 2018 it announced the purchase of Wilson Therapeutics for approximately $855 million and acquired Syntimmune for approximately $1.2 billion. In January 2020 it acquired Achillion Pharmaceuticals for approximately $930 million, adding immune-system research assets. In July 2020 it bought Portola Pharmaceuticals, broadening its portfolio into hematology, neurology, and critical care through products including Andexxa, a reversal agent for certain Factor Xa anticoagulants. Alexion also faced regulatory and reputational challenges. In 2020 it agreed to pay more than $21 million to resolve allegations that employees or representatives had bribed officials in Turkey and Russia to obtain or support regulatory approvals for Alexion medicines. The matter became one of the company’s most significant compliance controversies. AstraZeneca announced its agreement to purchase Alexion in 2020. The transaction, valued at approximately $39 billion, was completed in July 2021. Following completion, Alexion became AstraZeneca’s rare-disease business. Its principal commercial heritage remains centered on Soliris and the longer-acting complement inhibitor Ultomiris, while Strensiq, Kanuma, and Andexxa represent the company’s expansion into metabolic disease and critical care. As part of AstraZeneca, Alexion continues to operate as a specialist rare-disease organization rather than as an independent public pharmaceutical company.
- 2021
AstraZeneca acquisition closes
[1]Alexion becomes part of AstraZeneca after completion of the approximately $39 billion acquisition.
- 2020
Achillion and Portola acquisitions
[1]Alexion adds immune-system pipeline assets through Achillion and a commercial hematology and critical-care portfolio through Portola.
- 2018
Wilson Therapeutics and Syntimmune acquisitions
[1]The company expands its rare-disease and immunology pipeline through two acquisitions.
- 2017
Restructuring and Boston relocation announced
[1]Alexion announces workforce reductions, a Smithfield facility closure, and a headquarters move to Boston.
- 2015
Synageva is acquired and Strensiq is approved
[1]Alexion acquires Synageva and receives FDA approval for Strensiq for hypophosphatasia.
- 2011
Enobia Pharma is acquired
[1]Alexion acquires Enobia Pharma and obtains the asfotase alfa program for hypophosphatasia.
- 2007
Soliris receives FDA approval
[1]Eculizumab is approved in the United States for paroxysmal nocturnal hemoglobinuria.
- 2000
Headquarters move and Proliferon acquisition
[1]Alexion moves its headquarters to Cheshire, Connecticut, and acquires Proliferon, later renaming it Alexion Antibody Technologies.
- 1992
Alexion is founded in New Haven
[1]Steven Squinto and Leonard Bell establish Alexion Pharmaceuticals at Science Park in New Haven, Connecticut.
Products and positioning
A specialist rare-disease biopharmaceutical company focused on complement-mediated disorders, metabolic diseases, and other conditions with high unmet medical need. Its historical positioning combines highly targeted therapies, orphan-drug expertise, and premium-value medicines for small patient populations.
Complement inhibitor · 2007
Soliris
Soliris is the brand name for eculizumab, a monoclonal antibody that inhibits terminal complement activation. It was Alexion’s first major commercial product and was initially approved for paroxysmal nocturnal hemoglobinuria. Its use was subsequently associated with atypical hemolytic uremic syndrome. Soliris became central to Alexion’s rare-disease identity and is widely associated with the company’s high-value orphan-drug business model.
Long-acting complement inhibitor
Ultomiris
Ultomiris is the brand name for ravulizumab, a longer-acting complement inhibitor developed to extend the therapeutic franchise established by Soliris. It is used in rare complement-mediated disorders, including paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome. Its longer dosing interval was intended to reduce treatment frequency while preserving targeted complement inhibition.
Metabolic enzyme therapy · 2015
Strensiq
Strensiq is the brand name for asfotase alfa, a therapy for hypophosphatasia, an inherited metabolic disorder affecting bone mineralization and other physiological processes. Alexion obtained the underlying program through its acquisition of Enobia Pharma. FDA approval in 2015 marked a significant expansion beyond complement-mediated hematological and renal diseases.
Enzyme replacement therapy
Kanuma
Kanuma is the brand name for sebelipase alfa, a treatment for lysosomal acid lipase deficiency, a rare inherited disorder involving lipid metabolism. The product entered Alexion’s portfolio through the acquisition of Synageva Pharmaceuticals and broadened the company’s focus into another area of rare metabolic disease.
Anticoagulant reversal agent
Andexxa
Andexxa is the brand name for andexanet alfa, a recombinant modified factor Xa protein intended to reverse the anticoagulant effects of rivaroxaban and apixaban in patients experiencing life-threatening or uncontrolled bleeding. Alexion obtained the product through its acquisition of Portola Pharmaceuticals, adding a critical-care and hospital-focused medicine to its historically rare-disease-centered portfolio.
Controversies
Brand decisions
2020
Agreement to be acquired by AstraZenecaM&ABackground
Alexion had developed a specialized rare-disease portfolio and pipeline that complemented AstraZeneca’s broader pharmaceutical operations.
Action taken
AstraZeneca agreed to acquire Alexion for approximately $39 billion.
Aftermath
The transaction closed in July 2021, and Alexion became AstraZeneca’s rare-disease business.
Transaction value. Approximately $39 billion (2020 agreement; completed July 2021)
2017
Restructuring and headquarters relocationStrategyBackground
Alexion pursued organizational simplification and cost reduction amid changes in leadership and the need to focus resources on its rare-disease portfolio.
Action taken
The company announced a workforce reduction of approximately 20 percent, closure of the Smithfield manufacturing site, and relocation of headquarters to Boston.
Aftermath
The measures reshaped the company’s operating footprint and preceded further portfolio expansion through acquisitions.
2014
Rare-disease mRNA collaboration with ModernaOtherBackground
Alexion sought to explore messenger-RNA technology as a platform for developing treatments for rare inherited diseases.
Action taken
The company paid Moderna $100 million for options covering ten potential rare-disease products.
Aftermath
The program was discontinued in 2017 after animal studies did not support a sufficiently safe path to human development.
Option and collaboration payment. $100 million (2014)
Recent events
Genomenon and Alexion announce rare-disease genomics collaboration[2]
Reported:
Genomenon announced a collaboration with Alexion to produce genomic landscapes and make curated genetic datasets and information on therapies or clinical trials available to doctors, researchers, and clinicians through Genomenon's Mastermind Genomic Search Engine.
AstraZeneca completes acquisition of Alexion[3]
Reported:
AstraZeneca completed its $39 billion acquisition of Alexion Pharmaceuticals, following regulatory clearances. The deal included cash and newly issued AstraZeneca shares for Alexion shareholders.
- Unconfirmed
Alexion highly commended in Treasury Today's Adam Smith Awards[4]
Reported:
Alexion Pharmaceuticals was highly commended for “Harnessing the Power of Technology” in Treasury Today's Adam Smith Awards. The article says the recognition took place last week but does not provide a calendar date.
Weekdays and relative dates follow the original report; their exact calendar dates have not been verified.
AstraZeneca announces plan to acquire Alexion[5]
Reported:
AstraZeneca announced plans to acquire Alexion for approximately $39 billion. The boards of both companies approved the acquisition, which was expected to close in the third quarter of 2021 subject to regulatory clearances and shareholder approval.
Alexion raises 2020 revenue and earnings guidance[6]
Reported:
Alexion said it now expects fiscal 2020 non-GAAP earnings per share of $10.65 to $10.95 and total revenues of $5.55 billion to $5.60 billion, revising both ranges upward.
FDA approves Ultomiris for atypical hemolytic uremic syndrome[7]
Reported:
The U.S. Food and Drug Administration approved Alexion Pharmaceuticals’ Ultomiris for use in treating atypical hemolytic uremic syndrome (aHUS), according to the company.
FDA approves Ultomiris for atypical hemolytic uremic syndrome[8]
Reported:
The U.S. Food and Drug Administration approved Alexion Pharmaceuticals' Ultomiris for treating atypical hemolytic uremic syndrome (aHUS), its second rare blood disorder indication.
Sources8 sources
- 1Alexion Pharmaceuticalsen.wikipedia.org
- 2Genomenon与Alexion宣布罕见病基因组合作prweb.com
- 3阿斯利康完成对亚力兄的收购pharmaceutical-business-review.com
- 4Alexion获Treasury Today Adam Smith Awards高度表彰prnewswire.com
- 5阿斯利康宣布计划收购 Alexionpharmatimes.com
- 6Alexion上调2020年营收及盈利指引finanznachrichten.de
- 7FDA批准Ultomiris用于治疗非典型溶血性尿毒症综合征o.canada.com
- 8FDA 批准 Ultomiris 用于治疗非典型溶血性尿毒症综合征cnbc.com
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