Researchers to Present Nine Studies on Soliris® (eculizumab) in Patients with PNH and aHUS at EHA Congress

Alexion Pharmaceuticals, Inc. (Nasdaq: ALXN) today announced that researchers will present data relating to Soliris® (eculizumab) at the 16th Congress of the European Hematology Association (EHA), to be held June 9-12, 2011, in London. Findings will be presented from studies of Soliris as a treatment for patients with paroxysmal nocturnal hemoglobinuria (PNH) as well as a potential treatment for patients with atypical hemolytic uremic syndrome (aHUS). Abstracts summarizing these presentations were published today on the EHA website and can be accessed using the links below.

Soliris is approved for the treatment of patients with PNH in more than 35 countries worldwide. Alexion has submitted marketing applications to the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for Soliris as a treatment for patients with aHUS.

Soliris and PNH

The following abstract will be presented in a poster session on June 11, 2011 from 5:45 p.m. to 7:00 p.m. British Summer Time (BST):

Abstract #271, “Renal impairment is a risk factor for early mortality in patients with paroxysmal nocturnal hemoglobinuria (PNH),” Kim, et al.

http://www.eventure-online.com/eventure/publicAbstractView.do?id=162946&congressId=4634

The following abstract will be presented in a poster session on June 11, 2011 from 5:30 p.m. to 6:45 p.m. BST:

Abstract #841, “Clinical impact of uncontrolled complement activity in Japanese non-transfused patients with paroxysmal nocturnal hemoglobinuria,” Kanakura, et al.

http://www.eventure-online.com/eventure/publicAbstractView.do?id=162910&congressId=4634

The following abstract will be presented in a poster session on June 10, 2011 from 5:45 p.m. to 7:00 p.m. BST:

Abstract #254, “Long term outcomes in patients with paroxysmal nocturnal hemoglobinuria (PNH) with sustained eculizumab treatment,” Hillmen, et al.

http://www.eventure-online.com/eventure/publicAbstractView.do?id=163101&congressId=4634

The following abstract will be presented in a poster session on June 11, 2011 from 5:45 p.m. to 7:00 p.m. BST:

Abstract #833, “Pediatric diagnosis of paroxysmal nocturnal hemoglobinuria in the International PNH Registry,” Urbano, et al.

http://www.eventure-online.com/eventure/publicAbstractView.do?id=163116&congressId=4634

In addition, the following abstracts will be published in the EHA abstract book:

Abstract #1285, “PNH clonal expansion following bone marrow transplant: Case report,” Benavides.

http://www.eventure-online.com/eventure/publicAbstractView.do?id=162870&congressId=4634

Abstract #1504, “Poor clinical outcomes in non-transfused patients with paroxysmal nocturnal hemoglobinuria (PNH),” Jang.

http://www.eventure-online.com/eventure/publicAbstractView.do?id=162977&congressId=4634

Soliris and aHUS

The following abstract will be presented in a poster session on June 10, 2011 from 5:45 p.m. to 7:00 p.m., BST:

Abstract #396, “Eculizumab therapy for atypical hemolytic uremic syndrome in pediatric patients: Efficacy and safety outcomes from a retrospective study,” Simonetti, et al.

http://www.eventure-online.com/eventure/publicAbstractView.do?id=162762&congressId=4634

The following abstracts will be presented in a poster session on June 12, 2011 from 5:30 p.m. to 6:45 p.m. BST:

Abstract #980, “A phase II study of eculizumab in patients with atypical hemolytic uremic syndrome receiving chronic plasma exchange/infusion,” Loirat, et al.

http://www.eventure-online.com/eventure/publicAbstractView.do?id=162462&congressId=4634

Abstract #979, “Eculizumab efficacy and safety in patients with atypical hemolytic uremic syndrome resistant to plasma exchange/infusion,” Loirat, et al.

http://www.eventure-online.com/eventure/publicAbstractView.do?id=162419&congressId=4634

About Soliris

Soliris is a first-in-class terminal complement inhibitor developed from the laboratory through regulatory approval and commercialization by Alexion. Soliris has been approved in the U.S., European Union, Japan and other territories as the first treatment for patients with PNH, a debilitating, ultra-rare and life-threatening blood disorder defined by chronic uncontrolled complement activation which causes chronic red blood cell destruction (hemolysis), leading to blood clots, organ failure, and shortened survival. Prior to these approvals, there were no therapies specifically available for the treatment of patients with PNH. Soliris (eculizumab) is not approved for the treatment of aHUS or any indication other than PNH. Alexion's breakthrough approach to complement inhibition has received some of the pharmaceutical industry's highest honors: the 2008 Prix Galien USA Award for Best Biotechnology Product with broad implications for future biomedical research and the 2009 Prix Galien France Award in the category of Drugs for Rare Diseases. More information on Soliris is available at www.soliris.net.

Important Safety Information

Soliris is generally well tolerated in patients with PNH. The most frequent adverse events observed in clinical studies of patients with PNH were headache, nasopharyngitis (runny nose), back pain and nausea. Treatment with Soliris should not alter anticoagulant management because the effect of withdrawal of anticoagulant therapy during Soliris treatment has not been established.

The U.S. product label for Soliris also includes a boxed warning: "Soliris increases the risk of meningococcal infections. Meningococcal infection may become rapidly life-threatening or fatal if not recognized and treated early. Vaccinate patients with a meningococcal vaccine at least two weeks prior to receiving the first dose of Soliris; revaccinate according to current medical guidelines for vaccine use. Monitor patients for early signs of meningococcal infections, evaluate immediately if infection is suspected, and treat with antibiotics if necessary." During PNH clinical studies, two out of 196 vaccinated PNH patients treated with Soliris experienced a serious meningococcal infection. Prior to beginning Soliris therapy, all patients and their prescribing physicians are encouraged to enroll in the PNH Registry, which is part of a special risk-management program that involves initial and continuing education and long-term monitoring for detection of new safety findings.

About Alexion

Alexion Pharmaceuticals, Inc. is a biopharmaceutical company focused on serving patients with severe and ultra-rare disorders through the innovation, development and commercialization of life-transforming therapeutic products. Alexion is the global leader in complement inhibition, and has developed and markets Soliris® (eculizumab) as a treatment for patients with PNH, a debilitating, ultra-rare and life-threatening blood disorder. Soliris is approved in more than 35 countries. Alexion is evaluating other potential indications for Soliris and is pursuing development of other innovative biotechnology product candidates in early stages of development. This press release and further information about Alexion Pharmaceuticals, Inc. can be found at: www.alexionpharma.com.

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