Biogen Idec Submits Application to FDA for First Long-Lasting Factor IX Therapy for Hemophilia B

  Biogen Idec Submits Application to FDA for First Long-Lasting Factor IX
  Therapy for Hemophilia B

 -- Half-life of long-lasting rFIXFc may enable prophylactic dosing every 1-2
                                   weeks --

Business Wire

WESTON, Mass. -- January 4, 2013

Today Biogen Idec (NASDAQ: BIIB) announced the company recently submitted a
Biologics License Application (BLA) to the U.S. Food and Drug Administration
(FDA) for the marketing approval of recombinant factor IX Fc fusion protein
(rFIXFc) for the treatment of hemophilia B. rFIXFc is the first product
candidate in a new class of long-lasting clotting factor therapies that are
being developed with the goals of reducing the burden of treatment for this
condition and enhancing protection from bleeding. The regulatory submission
was based on results from B-LONG, the largest registrational phase 3 clinical
study in hemophilia B to date.

“The submission to FDA of rFIXFc is an important milestone towards the
introduction of a long-lasting factor IX therapy which is the first major
treatment advance for the hemophilia B community in 15 years,” said Glenn
Pierce, M.D., Ph.D., senior vice president of Global Medical Affairs and chief
medical officer of Biogen Idec’s hemophilia therapeutic area. “Our Fc fusion
technology uses a natural pathway in the body to keep factor in circulation
longer. The clinical efficacy and safety data for rFIXFc were robust and
showed that dosing every one to two weeks provided significant protection from
bleeding. Based on these data, we believe rFIXFc has the potential to have a
major impact on the global adoption of prophylactic treatment in hemophilia B,
helping patients prevent bleeding episodes and potentially reduce their
long-term consequences.”

Biogen Idec’s BLA submission to the U.S. FDA for rFVIIIFc for use in patients
with hemophilia A is on track for filing in 1H 2013.

About the Fc Fusion Technology Platform

rFIXFc is a clotting factor developed using Biogen Idec’s novel and
proprietary monomeric Fc fusion technology, which makes use of a naturally
occurring pathway that delays the destruction of factor and cycles it back
into the bloodstream, resulting in a longer circulating half-life.

With this technology, rFIXFc is designed to provide long-lasting protection
from bleeding and reduce the treatment burden associated with hemophilia B,
which currently can require more than 100 injections annually for prophylaxis
with commercially-available factor IX products. Fc fusion technology is used
in seven FDA-approved products for the long-term treatment of chronic diseases
including rheumatoid arthritis, psoriasis and platelet disorders.

About Hemophilia B

Hemophilia B is a rare, inherited disorder in which the ability of a person's
blood to clot is impaired. Hemophilia B occurs in about one in 25,000 male
births annually and is caused by having substantially reduced or no factor IX
activity, which is needed for normal blood clotting. People with hemophilia B
therefore need injections of factor IX to restore the coagulation process and
prevent frequent bleeds that could otherwise lead to pain, irreversible joint
damage and life-threatening hemorrhages. The Medical and Scientific Advisory
Council of the National Hemophilia Foundation recommends prophylaxis as the
optimal therapy for people with severe hemophilia B. Currently, prophylaxis in
hemophilia B typically requires injections up to three times per week to
maintain a sufficient circulating level of clotting factor.

About the Biogen Idec and Sobi Collaboration

Biogen Idec and Swedish Orphan Biovitrum (Sobi) are partners in the
development and commercialization of rFIXFc in hemophilia B and rFVIIIFc in
hemophilia A. 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.

AboutBiogen Idec

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

Safe Harbor

This press release contains forward-looking statements, including statements
about the commercialization and impact of long-lasting hemophilia therapies
and regulatory filings. 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 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.

Contact:

Biogen Idec Media Contact:
Jeff Boyle, 781-464-3260
Senior Director, Public Affairs
or
Biogen Idec Investor Relations Contact:
Kia Khaleghpour, 781-464-2442
Director, Investor Relations