Biogen Idec Demonstrates Commitment to Advancing Hemophilia Research and Care at Annual ASH Meeting

– 10 Abstracts, Including Oral Presentation, Highlight Data from Hemophilia Research and Development Program –

CAMBRIDGE, Mass.–(December 3, 2013)–Biogen Idec (NASDAQ: BIIB) will present new data from its hemophilia clinical development and research programs at the 55th Annual Meeting of the American Society of Hematology (ASH), taking place in New Orleans, December 7-10. Reflecting Biogen Idec’s commitment to transform hemophilia care, researchers will discuss 10 abstracts covering the breadth of the company’s comprehensive basic and clinical research programs. This includes new, interim data from Phase 3 studies in pediatric populations evaluating the company’s investigational long-lasting recombinant factor VIII Fc fusion protein candidate, ELOCTATETM, for hemophilia A and factor IX Fc fusion protein candidate, ALPROLIXTM, for hemophilia B.

“These new data from our groundbreaking research and development programs demonstrate our commitment to improving hemophilia treatment,” said Glenn Pierce, M.D., Ph.D., senior vice president of Global Medical Affairs and chief medical officer at Biogen Idec’s hemophilia therapeutic area. “We are excited to share our findings with physicians on the front lines of hemophilia management to further the understanding of the disorder.”

The titles of key Biogen Idec presentations are as follows:

ELOCTATE

• Pharmacokinetics of Recombinant Factor VIII Fc Fusion Protein (rFVIIIFc) in Pediatric Subjects with Hemophilia A: An Interim Analysis of the Kids A-LONG Study – Poster #3609 – Monday, December 9 – 6:00-8:00 PM (CST)
• Dosing Long-Lasting Recombinant Factor VIII Fc Fusion Protein: Experience in the A-LONG Study – Poster #3598 – Monday, December 9 – 6:00-8:00 PM (CST)
• The Bleeding Tendency In Relation To Predicted FVIII Activity Levels In Severe Hemophilia A Patients Treated With Recombinant Factor VIII Fc Fusion Protein – Poster #3590 – Monday, December 9 – 6:00-8:00 PM (CST)

ALPROLIX

• Association of Bleeding Tendency with Time Under Target FIX Activity Levels in Severe Hemophilia B Patients Treated with Recombinant Factor IX Fc Fusion Protein – Poster #2349 – Sunday, December 8 – 6:30-8:30 PM (CST)
• Pharmacokinetics, Safety and Efficacy of Long-lasting Recombinant Factor IX Fc Fusion Protein (rFIXFc) in Adolescent Subjects with Hemophilia B: A Subgroup Analysis of the B-LONG Study – Poster #2350 – Sunday, December 8 – 6:30-8:30 PM (CST)
• Pharmacokinetics of Recombinant Factor IX Fc Fusion Protein (rFIXFc) in Pediatric Subjects with Hemophilia B: An Interim Analysis of the Kids B-LONG Study – Poster #3599 – Monday, December 9 – 6:00-8:00 PM (CST)

Hemophilia Health Outcomes Research

• Psychometric Evaluation of Health-Related Quality of Life Data from the A-LONG and B-LONG Hemophilia Clinical Trials – Oral Presentation/Abstract #423 – Monday, December 9 – 11:00 AM (CST)

Nonclinical Research

• Evidence for Flexible Tethering of Fc to FVIII in Recombinant FVIII-Fc Fusion Protein rFVIIIFc – Poster #1102 – Saturday, December 7 – 5:30-7:30 PM (CST)
• Immunohistochemical Staining of rFVIIIFc and rFVIII in Liver Cells Differentiates between a VWF-Dependent and Independent Clearance Pathway in Mice – Poster #2331 – Sunday, December 8 – 6:30-8:30 PM (CST)
• An Immunodeficient Mice Model with Circulating Human Platelets to Evaluate the Platelet Clearance and Pharmacokinetics of Platelet-targeted Coagulator Factor VIIa – Abstract #2345 – Sunday, December 8 – 6:30-8:30 PM (CST)

Full session details and data abstracts for the 2013 Annual Meeting can be found on the ASH website at http://www.hematology.org/Meetings/Annual-Meeting/; full-text abstracts will be published in the December 6 issue of Blood, the journal of ASH.

Regulatory applications for ELOCTATE and ALPROLIX are currently under review in several countries including the U.S., Canada and Australia.

About the Fc Fusion Technology Platform

ELOCTATE and ALPROLIX were developed using Fc fusion technology, which takes advantage of a naturally occurring pathway that delays the breakdown of IgG1 (protein commonly found in the body) by recycling it back into the bloodstream. This technology is thought to be responsible for the prolonged time that ELOCTATE and ALPROLIX circulate in the body. While Fc fusion is an established technology that has been used for more than 15 years, Biogen Idec is the only company to apply it in hemophilia.

About Hemophilia

Hemophilia is a rare, inherited disorder in which the ability of a person’s blood to clot is impaired. There are different types of hemophilia depending on which clotting protein, or factor, is missing or reduced, including hemophilia A (factor VIII deficiency) and hemophilia B (factor IX deficiency). Hemophilia A occurs in about one in 5,000 male births annually, affecting about 16,000 people in the U.S. Hemophilia B is less common, accounting for about one in 25,000 male births annually, and approximately 3,000 people in the U.S. Both forms of hemophilia occur more rarely in females.

People with hemophilia can experience bleeding episodes that can cause pain, irreversible joint damage and life-threatening hemorrhages. Prophylactic infusions of factor VIII or IX can restore the coagulation process, as well as reduce or prevent new bleeding episodes. The Medical and Scientific Advisory Council of the National Hemophilia Foundation recommends prophylaxis as the optimal therapy for people with severe hemophilia.

About the Biogen Idec and Sobi Collaboration

Biogen Idec and Swedish Orphan Biovitrum (Sobi) are partners in the development and commercialization of ELOCTATE for hemophilia A and ALPROLIX for hemophilia B. Biogen Idec leads development, has manufacturing rights, and has commercialization rights in North America and all other regions excluding the Sobi territory. Sobi has the right to opt in to assume final development and commercialization in Europe (including Russia), the Middle East and Northern Africa.

About Biogen Idec

Through cutting-edge science and medicine, Biogen Idec discovers, develops and delivers to patients worldwide innovative therapies for the treatment of neurodegenerative diseases, hemophilia and autoimmune disorders. Founded in 1978, Biogen Idec is the world’s oldest independent biotechnology company. Patients worldwide benefit from its leading multiple sclerosis therapies, and the company generates more than $5 billion in annual revenues. For product labeling, press releases and additional information about the company, please visit www.biogenidec.com.

Biogen Idec Safe Harbor

This press release contains forward-looking statements, including statements about the potential advances, impact and therapeutic effect of ELOCTATE and ALPROLIX, our investigational long-lasting recombinant factor product candidates. These statements may be identified by words such as “believe,” “expect,” “may,” “plan,” “potential,” “will” and similar expressions, and are based on our current beliefs and expectations. Drug development and commercialization involve a high degree of risk. Factors which could cause actual results to differ materially from our current expectations include the risk that unexpected concerns may arise from additional data or analysis, regulatory authorities may require additional data or information or further studies, or may fail to approve or may delay approval of our drug candidates, or we may encounter other unexpected hurdles. For more detailed information on the risks and uncertainties associated with our drug development and commercialization activities, please review the Risk Factors section of our most recent annual or quarterly report filed with the Securities and Exchange Commission. Any forward-looking statements speak only as of the date of this press release and we assume no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

SOURCE: Biogen Idec