Press Releases
November 10, 2009

Researchers to Present Additional Data on Soliris(R) (eculizumab) for the Treatment of Patients With PNH at the ASH Annual Meeting

CHESHIRE, Conn., Nov 10, 2009 (BUSINESS WIRE) -- Alexion Pharmaceuticals, Inc. (Nasdaq: ALXN) today announced that researchers are scheduled to present data relating to Soliris(R) (eculizumab) as a treatment for patients with paroxysmal nocturnal hemoglobinuria (PNH) during the 51st Annual Meeting of the American Society of Hematology (ASH), to be held December 5 - 8, 2009 at the Ernst N. Morial Convention Center in New Orleans. Physicians are also scheduled to report on their experience with eculizumab in patients with atypical Hemolytic Uremic Syndrome (aHUS) during the meeting. Abstracts summarizing these presentations were published today on the ASH web site and can be accessed using the links provided below. Soliris is a complement inhibitor approved for the treatment of PNH to reduce hemolysis. Soliris is currently under investigation for the treatment of aHUS.

The following abstract will be presented in a poster session on Saturday, December 5, 2009 from 5:30 - 7:30 p.m., Central Standard Time (CST):

"Chronic Renal Insufficiency in Japanese Patients with Paroxysmal Nocturnal Hemoglobinuria (PNH): Improvement with Eculizumab Treatment in the Long-Term Follow-up of the AEGIS Study," Kanakura, et al.

Abstract: http://ash.confex.com/ash/2009/webprogram/Paper16844.html.

The following abstracts will be presented in a poster session on Sunday, December 6, 2009 from 6:00 - 8:00 p.m. CST:

"Successful Treatment of aHUS Recurrence and Arrest of Plasma Exchange Resistant TMA Post-Renal Transplantation with the Terminal Complement Inhibitor Eculizumab," Legault and Boelkins.

Abstract: http://ash.confex.com/ash/2009/webprogram/Paper16845.html.

"Effects of Eculizumab Therapy in Patients with Paroxysmal Nocturnal Hemoglobinuria (PNH) Receiving Concurrent Immunosuppressive Therapy for Bone Marrow Insufficiency," Schrezenmeier, et al. Poster II-979.

Abstract: http://ash.confex.com/ash/2009/webprogram/Paper16843.html.

"Identification and Clinical Significance of Type II Granulocytes Among Patients with Paroxysmal Nocturnal Hemoglobinuria (PNH) Identified Using Multiparameter High-Sensitivity Flow Cytometry," Movalia, et al.

Abstract: http://ash.confex.com/ash/2009/webprogram/Paper24600.html.

The following abstracts will be presented in a poster session on Monday, December 7, 2009 from 6:00 - 8:00 p.m. CST:

"Clinical Impact of Unregulated Terminal Complement Activity in Never-Transfused Patients with Paroxysmal Nocturnal Hemoglobinuria," Muus, et al.

Abstract: http://ash.confex.com/ash/2009/webprogram/Paper18021.html.

"Terminal Complement Inhibitor Eculizumab Improves Complement-Mediated Platelet Consumption and Thrombocytopenia in Patients with Paroxysmal Nocturnal Hemoglobinuria (PNH)," Socie, et al.

Abstract: http://ash.confex.com/ash/2009/webprogram/Paper18023.html.

About Soliris

Soliris has been approved by the U.S. Food and Drug Administration (March 2007), the European Commission (June 2007), Health Canada (January 2009) and Australia's Therapeutic Goods Administration (February 2009) as the first treatment for all patients with PNH, an ultra-rare, debilitating and life-threatening blood disorder defined by chronic hemolysis, or the destruction of red blood cells. Prior to these approvals, there were no therapies specifically available for the treatment of PNH. More information on Soliris is available at www.soliris.net.

Important Safety Information

Soliris is generally well tolerated. The most frequent adverse events observed in clinical studies were headache, nasopharyngitis (a 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 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 working to develop and deliver life-changing drug therapies for patients with serious and life-threatening medical conditions. Alexion is engaged in the discovery, development and commercialization of therapeutic products aimed at treating patients with a wide array of severe disease states, including hematologic and kidney diseases, transplant, cancer, and autoimmune disorders. Soliris is Alexion's first marketed product. Alexion is evaluating other potential indications for Soliris as well as other formulations of eculizumab for additional clinical indications, and is pursuing development of other antibody 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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SOURCE: Alexion Pharmaceuticals, Inc.

Alexion Pharmaceuticals, Inc.
Irving Adler, 203-271-8210
Sr. Director Corporate Communications
or
Makovsky & Company
Media:
Kristie Kuhl, 212-508-9642
or
Rx Communications
Investors:
Rhonda Chiger, 917-322-2569

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