New research evaluating substantial disease burden of PNH presented at European Hematology Association

Alexion Pharmaceuticals, Inc. (Nasdaq: ALXN) today announced new research evaluating the substantial disease burden of paroxysmal nocturnal hemoglobinuria (PNH), an ultra-rare blood disorder, in patients worldwide. The International PNH Registry, involving 580 patients from 99 sites in 14 countries as of May 2010, found that the debilitating symptoms and life-threatening complications of PNH are similar across patient populations around the world. Data from a separate Asian patient registry, which included 286 patients with PNH in South Korea, examined the clinical manifestations of PNH and concluded that thrombosis is a strong predictor of mortality in these patients. The findings of these patient registries support the need for treatment with Soliris^® (eculizumab), a first-in-class terminal complement inhibitor, to improve the prognosis and quality of life for patients living with PNH. The data were presented at the 15^th Congress of the European Hematology Association held in Barcelona, Spain on June 10-13, 2010.

“Clinical Symptoms of Hemolysis Are Predictive of Disease Burden and Mortality in Asian Patients with Paroxysmal Nocturnal Hemoglobinuria”

"These data quantify the severe and consistent impact of PNH on patients around the world and make clear the specific risks faced by patients in Asia," said Leonard Bell, M.D., Chief Executive Officer of Alexion. "The upcoming launch of Soliris in Japan represents our first major expansion into the Asia-Pacific region, where we will continue our disease education and access initiatives to provide the life-transforming benefits of Soliris to patients in a growing number of countries."

As previously announced, Alexion has accelerated plans for the launch of Soliris in Japan based on recent approval of pricing and reimbursement for Soliris by an advisory committee of Japan's Ministry of Health, Labour and Welfare (MHLW). The Company now expects to serve initial and increasing numbers of patients with PNH in Japan in the third and fourth quarters of 2010. In April 2010, Japan's MHLW approved Soliris as a treatment for patients with PNH, making it the first therapy approved in Japan for this patient population. Soliris is also approved in the United States, European Union, Australia, Canada and South Korea as a treatment for patients with PNH.

Global Disease Burden of PNH

Results from the International PNH Registry, which has enrolled 580 patients from 99 clinical sites in 14 countries as of May 2010, showed that a history of thrombotic events (TE) was present in patients across all clone sizes but was significantly higher in patients with larger clones. Patients with PNH clone ≥50% were more likely to have a history of TE (20%) compared to patients with smaller PNH clones> The registry, which continues to evaluate disease burden and determine the long-term natural history of PNH and treatment outcomes, also showed:

• Abdominal pain, chest pain, shortness of breath, and fatigue are prevalent symptoms in PNH patients.
• These patient-reported symptoms were equally prevalent across all PNH clone sizes and independent of history of bone marrow disorder.
• Transfusions are the most common treatment (55%), followed by anti-coagulants (36%), Soliris (34%) and immunosuppressive therapies (25%). As Alexion introduces Soliris in additional markets worldwide, sites participating in the registry are updating the information collected about specific treatments.

These data were presented by Dr. Alvaro Urbano-Ispizua and colleagues on Saturday, June 12 from 17:30-18:45 in Hall 6 in a poster presentation entitled, "Evaluation of Paroxysmal Nocturnal Hemoglobinuria Disease Burden in Patients Enrolled in the International PNH Registry" (Abstract #1022).

Fatigue and Impaired Quality of Life in Japanese Patients with PNH

Burden of disease data from the AEGIS study, a 12-week, open-label Phase II study of Soliris in 29 Japanese patients with PNH, was also presented at the EHA meeting. The data demonstrate that hemolysis, drives the risks and burden of disease in PNH independent of anemia. In this study, the primary endpoint of hemolysis reduction was achieved with high statistical significance with Soliris treatment. In addition, inhibition of terminal complement activation with Soliris also improved fatigue, dyspnea (difficulty breathing) and other significant morbidities of disease - also independent of anemia - in Japanese patients with PNH.

The data were presented by Dr. Yuzuru Kanakura and colleagues on Saturday, June 12 from 17:30-18:45 in Hall 6 in a poster presentation entitled, "Fatigue and Impaired Quality of Life in Patients with Paroxysmal Nocturnal Hemoglobinuria (PNH) is Associated with Hemolysis, But Not With Anemia" (Abstract #1042).

Clinical Manifestations and Disease Burden in Asian Patients with PNH

Results from a national data registry in South Korea retrospectively examined 286 PNH patients and demonstrated that Asian patients with PNH suffer similar disabling symptoms to those seen in other populations, including thrombosis, late stage kidney disease, liver dysfunction and symptoms of pulmonary hypertension. TE are a strong predictor of mortality in Asian patients (p<0.0001). Other findings include:

• Abdominal pain is a significant predictor of both early mortality and TE in Asian patients>
• Prominent symptoms of PNH such as hemoglobinuria (presence of hemoglobin in the urine), dyspnea and chest pain are also significant predictors of TE>
• The risk of TE is high across all granulocyte clone sizes, and presence of concomitant bone marrow dysfunction does not diminish the risk of TE.
• Despite medical intervention with supportive care (78% of patients used corticosteroids), patients continued to show disabling symptoms, progressive complications and early mortality.

The data were presented by Dr. Lee Jong Wook and colleagues on Friday, June 11 from 17:45-19:00 in Hall 6 in two poster presentations entitled, "Clinical Symptoms of Hemolysis Are Predictive of Disease Burden and Mortality in Asian Patients with Paroxysmal Nocturnal Hemoglobinuria" (Abstract # 0506) and "High Prevalence and Mortality Associated with Thromboembolism in Asian Patients with Paroxysmal Nocturnal Hemoglobinuria (PNH)" (Abstract #0505).