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

CHESHIRE, Conn., Nov. 10 /PRNewswire-FirstCall/ — Alexion Pharmaceuticals, Inc. today announced that the American Society of Hematology (ASH) has published additional data relating to Soliris(R) (eculizumab) as a treatment for patients with paroxysmal nocturnal hemoglobinuria (PNH). Data also have been published regarding initial experience with eculizumab in patients with two other rare diseases (Atypical Hemolytic Uremic Syndrome and Cold Agglutinin Disease). Abstracts will be presented at the 50th Annual Meeting of the American Society of Hematology, to be held December 6 to 9, 2008 at the Moscone Center in San Francisco.

The following abstracts will be presented as oral presentations on Monday, December 8, 2008. The abstracts and presentation information can be accessed through the links provided below.

   --  "Eculizumab Therapy Results in Rapid and Sustained Decreases in       Markers of Thrombin Generation and Inflammation in Patients with PNH,"       Dr. Ilene Weitz, et al.   Abstract: http://ash.confex.com/ash/2008/webprogram/Paper8206.html    --  "Eculizumab Reduces Pulmonary Hypertension Through Inhibition of       Hemolysis-Associated Nitric Oxide Consumption in Patients With       Paroxysmal Nocturnal Hemoglobinuria," Dr. Anita Hill, et al.   Abstract: http://ash.confex.com/ash/2008/webprogram/Paper9815.html   

The following abstracts will be presented in poster sessions on Monday, December 8, 2008.

   --  "Safety and Efficacy of the Terminal Complement Inhibitor Eculizumab       in Japanese Patients with Paroxysmal Nocturnal Hemoglobinuria: AEGIS       Phase II Clinical Study Results," Dr. Yuzuru Kanakura, et al.   Abstract: http://ash.confex.com/ash/2008/webprogram/Paper8331.html    --  "Modification of the Eculizumab Dose to Successfully Manage       Intravascular Breakthrough Hemolysis in Patients with Paroxysmal       Nocturnal Hemoglobinuria," Dr. Richard Kelly, et al.   Abstract: http://ash.confex.com/ash/2008/webprogram/Paper11166.html    --  "Effect of Reducing Intravascular Hemolysis on Ferritin Homeostasis in       Eculizumab Treated Paroxysmal Nocturnal Hemoglobinuria (PNH)       Patients," Dr. Alexander Roeth, et al.   Abstract: http://ash.confex.com/ash/2008/webprogram/Paper4867.html   

The following abstracts will be presented in poster sessions on Sunday, December 7, 2008.

   --  "Successful Treatment of Atypical Hemolytic Uremic Syndrome with the       Complement Inhibitor Eculizumab," Jens Nuernberger, et al.   Abstract: http://ash.confex.com/ash/2008/webprogram/Paper9272.html    --  "Long-term Efficacy of the Terminal Complement Inhibitor Eculizumab in       a Patient with Cold Agglutinin Disease (CAD)," Dr. Alexander Roeth, et       al.   Abstract: http://ash.confex.com/ash/2008/webprogram/Paper7013.html    The following abstract will be presented as an on-line publication.    --  "Efficacy of Eculizumab in a Plasmatherapy-Dependent Patient with       Atypical Hemolytic Uremic Syndrome with C3 mutation Following       Plasmatherapy Withdrawal," Dr Valerie Chatelet et al.    About Soliris  

Soliris is the first product approved for the treatment of patients with PNH in the U.S. and Europe. PNH is a rare, debilitating and life-threatening blood disorder defined by the destruction of red blood cells, or hemolysis. In patients with PNH, hemolysis can cause life-threatening thromboses, recurrent pain, kidney disease, disabling fatigue, impaired quality of life, severe anemia, pulmonary hypertension, shortness of breath and intermittent episodes of dark-colored urine (hemoglobinuria). Soliris, or eculizumab, is the only treatment that blocks this hemolysis.

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.

The U.S. product label for Soliris also includes a boxed warning: “Soliris increases the risk of meningococcal infections. 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.

   Please see full prescribing information at http://www.soliris.net/.    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. The Company 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 diseases, cancer and autoimmune disorders. In March 2007, the FDA granted marketing approval for the Company’s first product, Soliris for all patients with PNH. In June 2007, the European Commission granted marketing approval for Soliris in the European Union for all patients with PNH. The Company is evaluating other potential indications for Soliris, as well as other formulations of eculizumab for additional clinical indications. In addition, Alexion is pursuing development of an anti-CD200 monoclonal antibody as a treatment for patients with cancer, and evaluating 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: http://www.alexionpharma.com/.

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Alexion Pharmaceuticals, Inc.

CONTACT: Irving Adler, Sr., Director Corporate Communications of AlexionPharmaceuticals, Inc., +1-203-271-8210; or Mark Marmur of Makovsky & Company,+1-212-508-9670; or Rhonda Chiger of Rx Communications for Investors,+1-917-322-2569

Web Site: http://www.alexionpharma.com/http://www.soliris.net/