Alexion: Profile From The Company’s 2012 Annual Report

Overview

Alexion 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. Our marketed product Soliris^(R) (eculizumab) is the first and only therapeutic approved for patients with two ultra-rare and severe disorders resulting from chronic uncontrolled activation of the complement component of the immune system: paroxysmal nocturnal hemoglobinuria (PNH), an ultra-rare and life-threatening blood disorder, and atypical hemolytic uremic syndrome (aHUS), an ultra-rare and life-threatening genetic disease. We are also evaluating other potential indications for Soliris in other diseases in which chronic uncontrolled complement activation is the underlying mechanism, and we are progressing with other biotechnology product candidates in ultra-rare and severe disorders which are now in various stages of development. We were incorporated in 1992 and began commercial sale of Soliris in 2007.

Soliris is designed to inhibit a specific aspect of the complement component of the immune system and thereby treat inflammation associated with chronic disorders in the therapeutic areas of hematology, nephrology, transplant rejection, neurology and ophthalmology. Soliris is a humanized monoclonal antibody that blocks terminal complement activity at the doses currently prescribed. The initial indication for which we received approval for Soliris is PNH. PNH is an ultra-rare, debilitating and life-threatening, deficiency blood disorder defined by chronic uncontrolled complement activation leading to

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the destruction of red blood cells, or hemolysis. The chronic hemolysis in patients with PNH may be associated with 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 was approved for the treatment of PNH by the U.S. Food and Drug Administration(FDA) and the European Commission (EC) in 2007 and by Japan’s Ministry of Health, Labour and Welfare (MHLW) in 2010, and has been approved in several other territories. Additionally, in 2003 Soliris was granted orphan drug designation for the treatment of PNH in the United States, Europe, Japan and several other territories.

In September 2011, Soliris was approved by the FDA for the treatment of pediatric and adult patients with aHUS. aHUS is a genetic ultra-rare disease characterized by chronic uncontrolled complement activation and thrombotic microangiopathy, the formation of blood clots in small blood vessels throughout the body, causing a reduction in platelet count (thrombocytopenia) and life-threatening damage to the kidney, brain, heart and other vital organs. Also, in November 2011, the EC granted marketing authorization for Soliris to treat pediatric and adult patients with aHUS in Europe. In 2009, the FDA and EC granted Soliris orphan drug designation for the treatment of patients with aHUS.

Recent Developments

Acquisitions

On February 7, 2012, we acquired Enobia Pharma Corp. (Enobia), a privately held clinical-stage biotechnology company based in Montreal, Canada and Cambridge, Massachusetts, in a transaction expected to be accounted for as a business combination. The acquisition was intended to further our objective to develop and deliver therapies for patients with ultra-rare, severe, and life-threatening disorders. Enobia’s lead product candidate asfotase alfa, is a human recombinant targeted alkaline phosphatase enzyme-replacement therapy for patients suffering with hypophosphatasia (HPP), an ultra-rare, life-threatening, genetic metabolic disease for which there are no approved treatments. We made an upfront cash payment of $610 million, subject to purchase price adjustments, for 100% of Enobia’s capital stock. Additional contingent payments of up to an aggregate of $470 million would be due upon reaching various regulatory and sales milestones. We financed the acquisition through available cash and proceeds from our new credit facility as noted below.

On February 8, 2011, we acquired patents and assets from Orphatec Pharmaceuticals GmbH (Orphatec) related to an investigational therapy for patients with Type A molybdenum cofactor deficiency (MoCD), an ultra-rare disorder characterized by severe brain damage and rapid death in newborn infants. The acquisition was accounted for as a business combination. Orphatec is a privately held development stage biotechnology company with headquarters in Cologne, Germany. We made an upfront cash payment of approximately $3 million, and additional contingent payments of up to $42 million would be earned upon reaching various development, regulatory and commercial milestones. We will also make future payments to Orphatec for manufacturing, development and other services.

On January 28, 2011, we acquired Taligen Therapeutics, Inc. (Taligen), a privately held development stage biotechnology company based in Cambridge, Massachusetts, in a transaction accounted for as a business combination. The acquisition was intended to broaden our portfolio of preclinical compounds and to expand our capabilities in translational medicine. Preclinical compounds acquired from Taligen include product candidates for the potential treatment of patients with ophthalmic diseases such as age-related macular degeneration (AMD), as well as other novel antibody and protein regulators of the complement inflammatory pathways. We made an upfront cash payment of $112 million for 100% of Taligen’s equity interests. Additional contingent payments of up to an aggregate of $367 million would be due upon reaching various clinical efficacy and product approval milestones in both the U.S. and European Union for up to six product candidates.

Sales and Marketing

We have established an organization to support current and future sales of Soliris in the United States, in the major markets in Europe, Latin America and in Japan and in Asia Pacific countries. Our sales force is small compared to other drugs with similar gross revenues; however, we believe that a relatively smaller sales force is appropriate to effectively market Soliris due to the limited PNH and aHUS patient populations. If we receive regulatory approval in new territories, we may expand our own commercial organizations in such territories and market and sell Soliris through our own sales force in these territories. However, we will evaluate each jurisdiction on a country-by-country basis, and it is possible that we will promote Soliris in collaboration with marketing partners or rely on relationships with one or more companies with established distribution systems and direct sales forces in certain countries.

Customers

In the United States, our customers are primarily specialty distributors and specialty pharmacies which supply physician office clinics, hospital outpatient clinics, infusion clinics or home health care providers. We also sell Soliris to government agencies. Outside the United States, our customers are primarily hospitals, hospital buying groups, pharmacies, other health care providers and distributors.

During 2011, sales to our two largest customers accounted for 19% and 12% of our Soliris net product sales. During 2010, sales to our single largest customer accounted for 21%of our Soliris net product sales.

Because of factors such as the pricing of Soliris, the limited number of patients, the short period from product sale to patient infusion and the lack of contractual return rights, Soliris customers generally carry limited inventory. We also monitor inventory within our sales channels to determine whether deferrals are appropriate based on factors such as inventory levels, contractual terms and financial strength of distributors. To date, actual refunds and returns have been negligible.

Please also see Management’s Discussion and Analysis – Net Product Sales, and Note 17 of the Consolidated Financial Statements included in this Form 10-K, for financial information about geographic areas.

Employees

As of December 31, 2011, we had 1,008 full-time, world-wide employees, of which 385 were engaged in research, product development, manufacturing, and clinical development, 422 in sales and marketing, and 201 in administration, business development and finance. Our U.S. employees are not represented by any collective bargaining unit, and we regard the relationships with all our employees as satisfactory.

Chief Executive Officer/Founder

Leonard Bell, M.D. is the principal founder of Alexion, and has been a director of Alexion since February 1992 and the Company’s Chief Executive Officer since January 1992. From 1991 to 1992, Dr. Bell was an Assistant Professor of Medicine and Pathology and co-Director of the program in Vascular Biology at the Yale University School of Medicine. From 1990 to 1992, Dr. Bell was an attending physician at the Yale-New Haven Hospital and an Assistant Professor in the Department of Internal Medicine at the Yale University School of Medicine. Dr. Bell was a recipient of the Physician Scientist Award from the National Institutes of Health and Grant-in-Aid from the American Heart Association as well as various honors and awards from academic and professional organizations. His work has resulted in more than 20 scientific publications and 9 patent applications. Dr. Bell received his A.B. from Brown University and M.D. from Yale University School of Medicine. Dr. Bell is currently an Adjunct Assistant Professor of Medicine and Pathology at the Yale University School of Medicine.

Stock Split

On May 20, 2011, we effected a two-for-one stock split, paid in the form of a 100% stock dividend. Stockholders of record at the close of trading on May 2, 2011 were issued one additional share of common stock for each share owned by such shareholder. All share and per share data has been retroactively restated to reflect the stock split.

Litigation

On January 26, 2011, Novartis Vaccines & Diagnostics, Inc. (Novartis) filed a civil action against Alexion Pharmaceuticals, Inc. and other biopharmaceutical companies in the U.S. District Court for the District of Delaware. Novartis claims willful infringement by Alexion of U.S. Patent No. 5,688,688. Novartis seeks, among other things, monetary damages.

Products and Development Programs

The human immune system defends the body from attack or invasion by infectious agents or pathogens. This is accomplished through a complex system of proteins and cells, primarily complement proteins, antibodies

and white blood cells, each with a specialized function. Under normal circumstances, complement proteins, together with antibodies and white blood cells, act to protect the body by removing:

When activated by certain stimuli, the immune system triggers a series of enzymatic and biochemical reactions called the complement cascade that results in an inflammatory response. This inflammatory response is one of the immune system’s weapons against foreign pathogens or otherwise diseased tissue. However, under certain circumstances, the complement cascade may cause excessive or inappropriate activation, which may result in acute and chronic inflammatory conditions and damage to healthy tissues.

We have focused certain of our product development programs on anti-inflammatory therapeutics for diseases for which we believe current treatments are either non-existent or inadequate. Eculizumab is an antibody known as a C5 terminal complement inhibitor (C5 Inhibitor), which is designed to selectively block the production of inflammation-causing proteins of the complement cascade. We believe that selective suppression of this immune response may provide a significant therapeutic advantage relative to existing therapies. In addition to PNH and aHUS, for which the use of eculizumab has been approved in the United States and Europe and for PNH in several other territories, we believe that C5 Inhibitors may be useful in the treatment of a variety of other serious diseases and conditions resulting from uncontrolled complement activation.

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Our most advanced programs focus on two therapeutic areas: hematology and nephrology. We are also advancing our pipeline programs in neurology, metabolic disorders, oncology, and ophthalmology.

Soliris (eculizumab)

Soliris is designed to inhibit a specific aspect of the complement component of the immune system and thereby treat inflammation associated with chronic disorders in the therapeutic areas of hematology, nephrology including transplant rejection and neurology. Soliris is a humanized antibody which, administered at the doses currently prescribed, generally blocks complement activity for one to two weeks after a single dose.

Soliris was approved for the treatment of PNH by the FDA and the EC in 2007, by Japan’s MHLW in 2010 and has been approved in several other territories. Additionally, Soliris was granted orphan drug designation for the treatment of PNH in the United States, Europe, Japan and several other territories.

Soliris was approved for the treatment of aHUS by the FDA and the EC in 2011. Soliris was granted orphan drug designation for the treatment of aHUS in the United States and Europe.

Orphan drug designation generally entitles us to exclusivity for certain periods of time, subject to limited circumstances. However, if a competitive product that is the same as Soliris, as defined under the applicable regulations, is shown to be clinically superior to our product in the treatment of PNH, or if a competitive product is different from Soliris, as defined under

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the applicable regulations, the orphan drug exclusivity we have obtained may not restrict the approval of such competitive product.

Hematology

Paroxysmal Nocturnal Hemoglobinuria (PNH)

PNH is an ultra-rare, debilitating and life-threatening blood disorder in which an acquired genetic deficiency causes uncontrolled complement activation which leads to life-threatening complications. Patients with PNH have an acquired genetic deficiency in certain protective proteins on the surface of their blood cells, allowing their own complement system to attack and destroy these blood cells. Patients with PNH suffer from chronic complement activation of some of their blood cells and also hemolysis, or destruction of red blood cells caused by the C5 cleavage product C5b-9. This hemolysis is believed to lead to further clinical complications including thromboses, kidney disease, liver dysfunction, disabling fatigue, impaired quality of life, recurrent pain, shortness of breath, pulmonary hypertension, intermittent episodes of dark colored urine (hemoglobinuria), and anemia. The red blood cell destruction may be sufficiently large that recurrent blood transfusions are necessary to support normal red blood cell function. Approximately one-half of the patients with PNH die from the disease within 10 to 15 years of diagnosis. Soliris is the only therapy approved for the treatment of patients with PNH. We continue to work with researchers to expand the base of knowledge in PNH and the utility of Soliris to treat patients with PNH. Additionally, we are sponsoring multinational registries to gather information regarding the natural history of patients with PNH and the longer term outcomes during Soliris treatment.

Cold Agglutinin Disease (CAD)

We are aware that dosing is ongoing in an investigator-initiated Phase II study of eculizumab in patients for the treatment of CAD. CAD is a severe, ultra-rare complement-mediated autoimmune disease characterized by the presence of high concentrations of circulating complement-activating antibodies directed against red blood cells. As observed with PNH patients, CAD patients also suffer from the clinical consequences of severe hemolysis.

As blood is cooled during circulation through the distal parts of the arms and legs, specific antibodies bind to the red blood cells resulting in activation of the complement cascade and red blood cell lysis. Clinical manifestations of CAD include symptoms of chronic hemolysis such as fatigue, dyspnea, weakness, hemoglobinuria, kidney damage, pallor and jaundice as well as cold-induced circulatory symptoms ranging from mild discomfort to severe pain in affected limbs and tissues. In the most severe cases, complications of progressive hemolysis or anemia may result in death. Current therapies, including cold avoidance, corticosteroids, immunosuppressive drugs, intravenous immunoglobulin G and chemotherapy agents are largely ineffective in controlling hemolysis in patients with CAD.

Hematology/Nephrology

Atypical Hemolytic Uremic Syndrome (aHUS)

aHUS is an ultra-rare, chronic and life-threatening disease in which uncontrolled complement activation causes blood clots in small blood vessels throughout the body (thrombotic microangiopathy, or TMA) leading to kidney failure, stroke, heart attack and death.

In patients with aHUS, deficiency of naturally occurring complement inhibitors causes uncontrolled complement activation which leads to systemic TMA, the formation of blood clots in small blood vessels throughout the body causing a reduction in platelet count (thrombocytopenia) and life-threatening damage to the kidney, brain, heart and other vital organs. The prognosis for patients with aHUS is generally poor. Approximately 70% of patients with the most common mutation experience chronic renal insufficiency, chronic dialysis, or death within one year after the first clinical episode. Atypical HUS commonly recurs in patients who undergo renal transplantation. In addition, depending on the mutation, the disease can lead to loss of the transplanted kidney in up to approximately 90% of aHUS patients who undergo kidney transplantation.

Approximately 50% of patients with aHUS have been identified to have genetic mutations in at least one of the complement control proteins or neutralizing autoantibodies to complement regulatory factors, which can lead to uncontrolled complement activation. Excessive complement activation may contribute to the blood vessel inflammation and clotting by stimulating activation of white blood cells, platelets and the endothelial lining of blood vessels.

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Nephrology

Shiga-toxin producing E. Coli Hemolytic Uremic Syndrome (STEC-HUS)

STEC-HUS is a life-threatening, complement-mediated ultra-rare disorder that results from exposure to Enterohemorrhagic E.Coli, (EHEC). Our STEC-HUS development program was initiated in connection with the widespread outbreak of EHEC in Germany in May and June 2011. Many EHEC patients rapidly progressed to STEC-HUS during this outbreak. As in several other severe complement-mediated conditions, including atypical HUS, complement activation in STEC-HUS results in TMA. Although aHUS and STEC-HUS exhibit similar life-threatening TMA manifestations, aHUS and STEC-HUS are different disorders. Atypical HUS is a chronic genetic disease of uncontrolled complement activation, while STEC-HUS is not genetic and follows an isolated episode of infection. STEC-HUS is an ultra-rare disorder, comprising only a small sub-set of the already rare population of patients with EHEC. Following an authorization by the Paul-Ehrlich-Institut, Germany’s health care regulatory body for biologics, and an access program for patients initiated in May 2011, we initiated an open-label clinical trial to investigate eculizumab as a treatment for patients with STEC-HUS.

Dense Deposit Disease (DDD)

We are aware that independent investigators have commenced studies to evaluate eculizumab in patients with DDD as well as patients with a similar disease referred to as C3nef nephropathy. DDD also called Type II membrano-proliferative glomerulonephritis, is a rare form of glomerulonephritis, associated with genetic mutations in complement inhibitor genes leading to sustained complement activation and inflammation. Clinically, it is characterized by the onset of severe proteinuria (excess protein in the urine), often accompanied by nephrotic syndrome which is refractory to immunosuppressant therapy. In most cases, the disease evolves into chronic renal failure, requiring dialysis and renal transplantation.

Acute Humoral Rejection (AHR) in Presensitized Kidney Transplant Patients

Patients undergoing solid organ transplantation may experience severe AHR in the early post-transplant period. For example, in a patient undergoing a kidney transplant this may be characterized by the acute onset of renal dysfunction and rapid progression to destruction of the transplanted kidney.

AHR results when antibodies in the transplant recipient vigorously attack the blood vessels of the donor kidney. During severe AHR, these donor specific antibodies bind to the blood vessel lining of the donor organ and initiate activation of the complement cascade, resulting in severe blood vessel inflammation and clotting. Administration of a C5 inhibitor in animal models of AHR inhibits complement activation, tissue damage and transplant rejection.

The FDA has authorized our protocol to initiate multi-national, multi-site controlled clinical trials of eculizumab in presensitized renal transplant patients at elevated risk for AHR who will receive living donor grafts and enrollment in this trial has commenced. We are also aware that independent investigators have completed enrollment of patients in clinical trials to evaluate eculizumab in presensitized renal transplant patients at elevated risk for AHR. Preliminary results from one of the investigator initiated trials was published in September 2011 in the American Journal of Transplantation. We are also aware that an independent investigator has also started enrolling patients in a clinical trial to evaluate eculizumab in kidney transplant patients sensitized to their donor kidney due to an ABO blood group mismatch between donor and recipient.

Neurology

Myasthenia Gravis (MG)

MG is a rare autoimmune syndrome characterized by complement activation leading to failure of neuromuscular transmission. Patients with MG initially experience weakness in their ocular, or eye muscles, and the disease typically progresses to head, spinal, limb and respiratory muscles. Symptoms can include drooping eyelids, blurred vision, slurred speech, difficulty chewing or swallowing, weakness in the arms and legs and difficulty breathing. In an experimental animal model of MG, administration of a C5 Inhibitor was found to prevent experimentally acquired MG and to inhibit disease progression.

The FDA authorized our Investigational New Drug Application (IND) for studying the safety and efficacy of eculizumab in treating patients with MG. Enrollment has closed with 14 patients. Preliminary data from the Phase II trial demonstrated an encouraging disease improvement signal and was presented at the Myasthenia Gravis Foundation Annual Meeting in September 2011.

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Neuromyelitis Optica (NMO)

NMO is a rare autoimmune disease of the central nervous system (CNS) that affects the optic nerves and spinal cord. Individuals with NMO develop optic neuritis, which causes pain in the eye and vision loss, and transverse myelitis, which causes weakness, numbness, and sometimes paralysis of the arms and legs, along with sensory disturbances and loss of bladder and bowel control.

We are aware that independent investigators are examining the role of eculizumab for the treatment of patients with NMO. Enrollment in the investigator initiated trial has been completed.

Ophthalmology

Dry Age-Related Macular Degeneration (AMD)

Age-related macular degeneration is a medical condition usually affecting older adults in which uncontrolled complement activation results in a loss of vision in the center of the visual field (the macular) and complement-mediated damage to the retina. AMD is a major cause of visual impairment in older adults.

We are aware of an independent investigator who has completed enrollment of patients in a study evaluating the safety and efficacy of eculizumab as a treatment for the dry form of age-related macular degeneration.

Asfotase Alfa

Metabolic Diseases

Hypophosphatasia

HPP is an ultra-rare, genetic, and life-threatening metabolic disease characterized by defective bone mineralization and impaired phosphate and calcium regulation, leading to progressive damage to multiple vital organs including destruction and deformity of bones, profound muscle weakness, seizures, impaired renal function, and respiratory failure. The severe manifestations of the genetic deficiency in HPP affect people of all ages, and approximately 50% of infants with the disease do not survive past one year of age.HPP is caused by mutations in the gene encoding enzyme Tissue Nonspecific Alkaline Phosphatase. This enzyme normally breaks down substrates such as inorganic pyrophosphateand pyridoxal phosphate, which otherwise build up and inhibit bone mineralization.

Asfotase alfa, a targeted enzyme replacement therapy in Phase II clinical trials for patients with HPP, directly addresses the morbidities and mortality of HPP by targeting alkaline phosphatase directly to the deficient tissue. In this way, asfotase alfa is designed to normalize the genetically defective metabolic process and prevent or reverse the severe, crippling and life-threatening complications of dysregulated mineral metabolism in patients with HPP. We acquired Asfotase alfa in February 2012 in connection with our acquisition of Enobia.

cPMP

Molybdenum Cofactor Deficiency (MoCD) Disease Type A (MoCD Type A)

MoCD Type A is a rare metabolic disorder characterized by severe and rapidly progressive neurologic damage and death in newborns, MoCD Type A results from a genetic deficiency in cyclic Pyranopterin Monophosphate (cPMP), a molecule that enables production of certain enzymes, the absence of which allows neurotoxic sulfite to accumulate on the brain. To date, there is no approved therapy available for MoCD Type A. We acquired assets related to a cPMP replacement therapy from Orphatec Pharmaceuticals GmbH in February 2011. There has been some early clinical experience with the cPMP replacement therapy in a small number of children with MoCD type A.

TT30

TT30 is a novel alternative pathway complement inhibitor with a mechanism of action unique from Soliris. We acquired a portfolio of preclinical product candidates, including TT30, in January 2011 in connection with the purchase of all of the equity interests of Taligen. TT30 is currently being investigated in a Phase I single dose, dose escalating safety and pharmacology study.

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Samalizumab

Samalizumab is our proprietary humanized monoclonal antibody directed against the cell surface protein CD200. Samalizumab is designed to modulate the immune system and destroy tumors expressing the CD200 protein.

The FDA authorized our IND to evaluate the activity of samalizumab, an antibody to the immune regulator CD200, in patients with chronic lymphocytic leukemia (CLL). CLL is a type of cancer of the blood and bone marrow. CLL most commonly affects older adults, though it may occur at any age and rarely can affect children.

Multiple myeloma, also known as plasma cell myeloma, is the second-most common cancer of the blood. It is the most common type of plasma cell neoplasm. Multiple myeloma accounts for approximately 1% of all cancers and 2% of all deaths from cancer.

Enrollment and dosing has now been completed in our Phase I dose-escalation clinical study of samalizumab in patients with treatment refractory CLL or multiple myeloma. The trial enrolled 26 patients, and positive interim results from this trial were reported at the 2010 American Society for Hematology meeting.

Manufacturing

We currently rely on two manufacturing facilities, Alexion’s Rhode Island manufacturing facility (ARIMF) and Lonza Group AG and its affiliates (Lonza), for producing commercial and clinical quantities of Soliris. Our clinical and preclinical quantities of eculizumab, samalizumab and other product candidates are produced at ARIMF, at a third party facility or at both ARIMF and a third party facility. We also depend on a very limited number of third party providers for other services with respect to our clinical and commercial requirements, including product finishing, packaging, vialing and labeling.

We have various agreements with Lonza, with remaining total commitments of approximately $136,000 through 2018. Such commitments may be canceled only in limited circumstances. If we terminate certain supply agreements with Lonza without cause, we will be required to pay for product scheduled for manufacture under our arrangement. Under an existing arrangement with Lonza, we also pay Lonza a royalty on sales of Soliris manufactured at ARIMF.

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Patents and Proprietary Rights

Patents and other proprietary rights are important to our business. Our policy is to file patent applications to protect technology, inventions and improvements to our technologies that are considered important to the development of our business. We also rely upon our trade secrets, know-how, and continuing technological innovations, as well as patents that we have licensed or may license from other parties, to develop and maintain our competitive position.

We have filed several U.S. patent applications and international counterparts of certain of these applications. In addition, we have in-licensed several additional U.S. and international patents and patent applications. As of December 31, 2011, we own or in-license 77 U.S. patents and 52 U.S. patent applications. These patents and patent applications relate to technologies or products in the C5 Inhibitor program, high throughput screening, vectors, cancer, recombinant antibodies, and other technologies. As of December 31, 2011, we own or in-license 65 foreign patents and 208 pending foreign patent applications.

With respect to Soliris, we have an issued U.S. patent covering Soliris that will expire in 2021, taking into account patent term extension. In Europe, a corresponding issued patent covering Soliris expires in 2015 and, taking into account the Supplementary Certificates of Protection (SPC) that we have filed for in various European countries, exclusivity for Soliris will extend into 2020 in those countries in which an SPC is granted. Patents covering Soliris in Japan and other countries expire between 2015 and 2020. We owe royalties and other fees to owners of one or more patents in connection with the manufacture and sale of Soliris for PNH and aHUS, and we may owe royalties and fees to other third parties with respect to any previous or future manufacture and sale of Soliris and our product candidates.

We also own U.S. and foreign patents and patent applications for our product candidates other than Soliris. At present, each such product candidate is in early stage development and it is not known whether any such product candidate will ever be approved for human use and sale.

Our success will depend in part on our ability to obtain and maintain U.S. and international patent protection for our products and development programs, to preserve our trade secrets and proprietary rights, and to operate without infringing on the proprietary rights of third parties or having third parties circumvent our rights. Because of the length of time and expense associated with bringing new products through development and regulatory approval to the marketplace, the health care industry has traditionally placed considerable importance on obtaining patent and trade secret protection for significant new technologies, products and processes. Significant legal issues remain to be resolved as to the extent and scope of patent protection for biotechnology products and processes in the United States and other important markets outside of the United States. Accordingly, there can be no assurance that patent applications owned or licensed by us will issue as patents, or that any issued patents will afford meaningful protection against competitors. Moreover, once issued, patents are subject to challenge through both administrative and judicial proceedings in the United States and in foreign jurisdictions. Such proceedings include interference proceedings before the U.S. Patent and Trademark Office and opposition proceedings before the European Patent Office. Litigation may be required to enforce our intellectual property rights. Any litigation or administrative proceeding may result in a significant commitment of our resources and, depending on outcome, may adversely affect the validity and scope of certain of our patent or other proprietary rights.

We are aware of broad patents owned by others relating to the manufacture, use and sale of recombinant humanized antibodies, recombinant human antibodies, and recombinant human single chain antibodies. Soliris and some of our product candidates are either genetically engineered antibodies, including recombinant humanized antibodies, recombinant human antibodies, or recombinant human single chain antibodies. We have received notices from the owners of patents claiming that their patents may be infringed by the development, manufacture or sale of Soliris or some of our drug candidates. For example, in January 2011, Novartis filed a civil action in the U.S. District Court for the District of Delaware alleging that the manufacture of Soliris infringes their U.S. patent number 5,688,688. We are also aware of other patents owned by third parties that might be claimed by such third parties to be infringed by the development and commercialization of Soliris or some of our product candidates. In respect to some of these patents, we have obtained licenses, or expect to obtain licenses. However, with regard to such other patents, we have determined in our judgment that:

If any patent holder successfully challenges our judgment that our products do not infringe their patents or that their patents are invalid, we could be required to pay costly damages or to obtain a license to sell or develop our drugs. A required license may be costly or may not be available on acceptable terms, if at all. A costly license, or inability to obtain a necessary license,

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could materially and adversely affect our ability to commercialize our products, including Soliris.

We record actual and estimated royalties to third parties related to the sale and commercial manufacture of Soliris. These estimates are influenced by our assessment of the likelihood of third parties asserting that their patents are infringed by the manufacture or sale of Soliris and the likely outcome of any such assertion. On a periodic basis, as additional information becomes available, or based on specific events such as the outcome of litigation or settlement of claims, we may reassess the potential liability related to these matters and may revise these estimates, which could result in a material adverse adjustment to our operating results.

It is our policy to require our employees, consultants and parties to collaborative agreements to execute confidentiality agreements upon the commencement of employment or consulting relationships or collaborations with us. These agreements generally provide that all confidential information developed or made known during the course of the relationship with us is to be kept confidential and not to be disclosed to third parties except in specific circumstances. In the case of employees, the agreements also provide that all inventions resulting from work performed for us, utilizing our property or relating to our business and conceived or completed by the individual during employment shall be our exclusive property to the extent permitted by applicable law.

License Agreements

In March 1996, we entered into a license agreement with the Medical Research Council (MRC) whereby MRC granted to us worldwide non-exclusive rights to certain patents related to the humanization and production of monoclonal antibodies. We pay MRC royalties on a quarterly basis with respect to sales of Soliris. The royalty is payable until the expiration of the last patent covered by the license agreement, which is expected to be in 2015, except that royalties for sales in Canada will continue until January of 2017. MRC may terminate the license if we file for bankruptcy or become insolvent, or if we fail to perform our obligations under the agreement and such failure is not remedied within three months after delivery of notice. Under the agreement, we agreed to (a) make royalty payments with respect to sales of licensed products, (b) promote the sale of Soliris of good marketable quality, and (c) use reasonable endeavors to meet market demand for licensed products.

We are party to other license agreements related to the manufacture and sale of Soliris. Under an existing arrangement with Lonza, we pay Lonza a royalty on sales of Soliris manufactured at ARIMF.

Government Regulation

The preclinical studies and clinical testing, manufacture, labeling, storage, record keeping, advertising, promotion, export, and marketing, among other things, of our products and product candidates, including Soliris, are subject to extensive regulation by governmental authorities in the United States and other countries. In the United States, pharmaceutical products are regulated by the FDA under the Federal Food, Drug, and Cosmetic Act and other laws, including, in the case of biologics, the Public Health Service Act. Soliris is regulated by the FDA as a biologic. Biologics require the submission of a Biologics License Application (BLA) and approval by the FDA prior to being marketed in the United States. Manufacturers of biologics may also be subject to state regulation. Failure to comply with FDA requirements, both before and after product approval, may subject us and/or our partners, contract manufacturers, and suppliers to administrative or judicial sanctions, including FDA refusal to approve applications, warning letters, product recalls, product seizures, total or partial suspension of production or distribution, fines and/or criminal prosecution.

The steps required before a biologic may be approved for marketing of an indication in the United States generally include:

(1) preclinical laboratory tests and animal tests;

(2) submission to the FDA of an IND for human clinical testing, which must become effective before human clinical trials may commence;

(3) adequate and well-controlled human clinical trials to establish the safety and efficacy of the product;

(4) submission to the FDA of a BLA or supplemental BLA;

(5) FDA pre-approval inspection of product manufacturers; and

(6) FDA review and approval of the BLA or supplemental BLA.

Orphan Drug Designation

Under the Orphan Drug Act, the FDA may grant orphan drug designation to drugs intended to treat a “rare disease or condition,” which generally is a disease or condition that affects fewer than 200,000 individuals in the United States. Orphan drug designation must be requested before submitting a BLA or supplemental BLA. After the FDA grants orphan drug designation, the generic identity of the therapeutic agent and its potential orphan use are publicly disclosed by the FDA. Orphan drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process. If a product which has an orphan drug designation subsequently receives the first FDA approval for the indication for which it has such designation, the product is entitled to an orphan exclusivity period, in which the FDA may not approve any other applications to market the same drug for the same indication for seven years, except in limited circumstances.

Soliris has also received orphan drug designation for the treatment of PNH in the United States and in several other territories, including Europe, Australia and South Korea, which provides certain regulatory and filing fee advantages, including market exclusivity, except in limited circumstances, for several years after approval. In 2009, Soliris also received orphan drug designation for the treatment of patients with aHUS in the United States and Europe. In 2008, asfotase alfa orphan drug designation for the treatment of patients with hypophosphatasia in the United States and Europe.

Foreign Regulation

In addition to regulations in the United States, we are subject to a variety of foreign regulatory requirements governing human clinical trials and marketing approval for drugs. The foreign regulatory approval process includes all of the risks associated with FDA approval set forth above, as well as additional country-specific regulations. Whether or not we obtain FDA approval for a product, we must obtain approval of a product by the comparable regulatory authorities of foreign countries before we can commence clinical trials or marketing of the product in those countries. The approval process varies from country to country, and the time may be longer or shorter than that required for FDA approval. The requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary greatly from country to country.

For example, under European Union regulatory systems, we may submit marketing authorizations either under a centralized or decentralized procedure. The centralized procedure provides for the grant of a single marketing authorization that is valid for all European Union member states. The decentralized procedure provides for mutual recognition of national approval decisions, and the holder of a national marketing authorization may submit an application to the remaining member states. We submitted our Marketing Authorization Application for Soliris for the treatment of PNH to the European Medicines Agency (EMA) using the centralized procedure.

The European Union has had an established regulatory pathway for biosimilars since 2005 and has approved several biosimilar products. The approval of a biologic product biosimilar to one of our products marketed in the European Union could have a material impact on our business and may be significantly less costly to bring to market and may be priced significantly lower than our products.

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Reimbursement

Sales of pharmaceutical products depend in significant part on the coverage and reimbursement policies of government programs, including Medicare and Medicaid in the United States, and other third party payors. These health insurance programs may restrict coverage of some products by using payor formularies under which only selected drugs are covered, variable co-payments that make drugs that are not preferred by the payor more expensive for patients, and by using utilization management controls, such as requirements for prior authorization or prior failure on another type of treatment. Payors may especially impose these obstacles to coverage for higher priced drugs, and consequently Soliris may be subject to payor-driven restrictions.

In addition, in some foreign countries, the proposed pricing for a drug must be approved before it may be lawfully marketed. The requirements governing drug pricing vary widely from country to country. For example, the European Union provides options for its member states to restrict the range of medicinal products for which their national health insurance systems provide reimbursement and to control the prices and/or reimbursement of medicinal products for human use. A member state may approve a specific price or level of reimbursement for the medicinal product, or it may instead adopt a system of direct or indirect controls on the profitability of the company placing the medicinal product on the market, including volume-based arrangements. On a continuous basis, we engage with appropriate authorities on the operational, reimbursement, price approval and funding processes that are separately required in each country.

Competition

There are currently no approved drugs other than Soliris for the treatment of PNH and aHUS. However, many companies, including major pharmaceutical and chemical companies as well as specialized biotechnology companies, are engaged in activities similar to our activities. Universities, governmental agencies and other public and private research organizations also conduct research and may market commercial products on their own or through joint ventures. Many of these entities may have:

Many of these companies and organizations have significant experience in preclinical testing, human clinical trials, product manufacturing, marketing, sales and distribution and other regulatory approval and commercial procedures. They may also have a greater number of significant patents and greater legal resources to seek remedies for cases of alleged infringement of their patents by us to block, delay or compromise our own drug development process.

We compete with large pharmaceutical companies that produce and market synthetic compounds and with specialized biotechnology firms in the United States, Europe and elsewhere, as well as a growing number of large pharmaceutical companies that are applying biotechnology to their operations. A number of biotechnology and pharmaceutical companies are developing new products for the treatment of the same diseases being targeted by us; in some instances, these products have already entered clinical trials or are already being marketed. Other companies are engaged in research and development based on complement proteins.

Several companies have either publicly announced their intentions to develop drugs which target the inflammatory effects of complement in the immune system or have had programs to develop complement inhibitor therapies. We believe that our potential C5 Inhibitors differ substantially from those of our potential competitors due to our compounds’ demonstrated ability to specifically intervene in the complement cascade, for potentially prolonged periods of time. We believe this action to be the optimal point so that the disease-causing actions of complement proteins are inhibited, while the normal disease-preventing functions of complement proteins and other aspects of immune function remain intact.

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EXECUTIVE OFFICERS OF THE COMPANY

The executive officers of the Company and their respective ages and positions as of February 11, 2012 are as follows: