BIOGEN IDEC AND SOBI ANNOUNCE POSITIVE TOP-LINE RESULTS FROM PHASE 3 STUDY INVESTIGATING LONG-LASTING RECOMBINANT FACTOR VIII FC FUSION PROTEIN IN HEMOPHILIA A

  * Individualized and weekly prophylactic regimens resulted in low single-digit
    median annualized bleeding rates
  * 98% of bleeding episodes were controlled with one or two injections of
    rFVIIIFc
  * No patients developed inhibitors to rFVIIIFc
  * The primary efficacy and safety objectives were met and Biogen Idec plans to
    submit an application to US FDA in first half 2013

Weston, Mass and Stockholm, Sweden - October 31, 2012 - Biogen Idec (NASDAQ:
BIIB) and Swedish Orphan Biovitrum (Sobi) (STO: SOBI) today announced positive
results from A-LONG, a clinical study that evaluated a new long-lasting clotting
factor candidate in people with hemophilia A.  Hemophilia A is a rare inherited
disorder that impairs blood coagulation.

Top-line results from A-LONG, a global, multi-center, Phase 3 clinical study of
the companies' long-lasting recombinant Factor VIII Fc fusion protein
(rFVIIIFc), showed that rFVIIIFc was effective in the control and prevention of
bleeding, routine prophylaxis and perioperative management. Recombinant FVIIIFc
was generally well-tolerated. Additional analyses of the A-LONG study are
ongoing, and the companies anticipate presenting detailed results at a future
scientific meeting.

Biogen Idec plans to submit a Biologics License Application (BLA) to the U.S.
Food and Drug Administration (FDA) in the first half of 2013. Consistent with
guidelines published by the European Medicines Agency (EMA) that require a study
in children less than 12 years of age prior to filing, Biogen Idec and Sobi
expect to file a Marketing Authorization Application with the EMA upon
completion of the ongoing Kids A-LONG study.

 "These top-line results demonstrated that rFVIIIFc has the potential to enhance
the care of people living with hemophilia A by offering protection from bleeding
with reduced treatment burden," 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. "We share the enthusiasm of the hemophilia
community including the study participants and clinical investigators who
supported the rapid enrollment of the A-LONG study. We are diligently working to
prepare our regulatory submission with the goal of providing rFVIIIFc to people
with hemophilia A as soon as possible."

"We are very encouraged by the positive A-LONG study results, which support the
application of Fc fusion technology in hemophilia A to prolong factor activity
and potentially offer extended protection from bleeding," said Geoffrey
McDonough, M.D., Chief Executive Officer of Sobi. "The A-LONG findings, coupled
with recently announced results from the B-LONG study of our companies' long-
lasting recombinant Factor IX Fc fusion product candidate for hemophilia B,
represent a major step forward for the hemophilia community."

Summary of Key Data from A-LONG
In the A-LONG study, 165 male patients aged 12 years and older were enrolled.
The A-LONG study had three treatment arms: individualized prophylaxis, weekly
prophylaxis and episodic (on-demand) treatment (Arms 1, 2 and 3, respectively).
In a subgroup of patients across treatment arms, rFVIIIFc was evaluated in the
perioperative management of patients who required a major surgical procedure
during the study.

Overall, 93 percent of patients completed the study. Recombinant FVIIIFc was
generally well-tolerated. No inhibitors to rFVIIIFc were detected and no cases
of anaphylaxis were reported in any patients, all of whom switched from
commercially-available Factor VIII products. No serious adverse events were
assessed to be related to drug by the investigator. The most common adverse
events (incidence of more than / equal 5 percent) occurring outside of the
perioperative management period were nasopharyngitis, arthralgia, headache and
upper respiratory tract infection.

The median annualized bleeding rates (ABR), including spontaneous and traumatic
bleeds, were 1.6 in the individualized prophylaxis arm, 3.6 in the weekly
prophylaxis arm and 33.6 in the episodic treatment arm. In the individualized
prophylaxis arm, the median dosing interval was 3.5 days. During the last three
months on study, 30 percent of patients in the individualized prophylaxis arm
achieved a mean dosing interval of five days.

Control of bleeding was assessed in all patients who experienced a bleeding
episode during the study. Overall, 98 percent of bleeding episodes were
controlled by one or two injections of rFVIIIFc.

In addition, rFVIIIFc was assessed in the perioperative management of nine
patients undergoing nine major surgical procedures. The treating physicians
rated the hemostatic efficacy of rFVIIIFc as excellent or good in 100 percent of
these surgeries.

A-LONG included pharmacokinetic (PK) analysis of rFVIIIFc in all patients in the
study.  In a protocol-defined subset of patients with extensive PK sampling, the
approximate terminal half-life of rFVIIIFc was 19.0 hours compared to 12.4 hours
for Advate® [antihemophilic factor (recombinant), plasma/albumin-free method],
consistent with the results obtained in the Phase 1/2a study of rFVIIIFc.

Webcast
Biogen Idec and Sobi senior management will host a webcast to discuss the A-LONG
study results today, October 31, 2012, at 2:00 p.m. CET . Previously announced
results from the B-LONG Phase 3 study in hemophilia B will also be discussed.
Participants may access the webcast through the Investors section of Biogen
Idec's homepage, www.biogenidec.com.

About the A-LONG Study and the rFVIIIFc Program
A-LONG was a global, open-label, multi-center Phase 3 study that evaluated the
efficacy, safety and pharmacokinetics of intravenously-injected rFVIIIFc. The
study was designed to evaluate rFVIIIFc in the control and prevention of
bleeding, routine prophylaxis and perioperative management in patients with
hemophilia A. A-LONG involved 60 hemophilia treatment centers in 19 countries on
six continents.

The A-LONG study had three treatment arms. In Arm 1 (individualized prophylaxis;
n=118), patients were treated with 25-65 IU/kg of rFVIIIFc, at an interval of
every three to five days, which was individualized to maintain factor trough
levels sufficient to prevent bleeding. In Arm 2 (weekly prophylaxis; n=24),
patients were treated with a weekly dose of 65 IU/kg. In Arm 3 (episodic
treatment; n=23), patients received rFVIIIFc as needed for bleeding. In a
subgroup of patients across treatment arms, rFVIIIFc was evaluated in the
surgical setting.

The primary efficacy and safety measures were the annualized bleeding rate and
the incidence of adverse events including inhibitor development in patients
studied for up to approximately 52 weeks. Secondary endpoints included response
to treatment of bleeding episodes and the pharmacokinetics of rFVIIIFc versus
Advate.

Ongoing clinical studies of rFVIIIFc include the Kids A-LONG and ASPIRE studies.
Kids A-LONG is a Phase 3, open-label study in previously-treated children with
hemophilia A under age 12, which is actively recruiting patients. ASPIRE is a
long-term open-label study for patients who completed the A-LONG study or who
complete the Kids A-LONG study.

About the Fc Fusion Technology Platform
Recombinant FVIIIFc is a clotting factor developed using Biogen Idec's novel and
proprietary monomeric Fc fusion technology, which makes use of a natural pathway
to recycle rFVIIIFc in circulation and enable it to remain in the body longer.
With this technology, rFVIIIFc is designed to provide long-lasting protection
from bleeding and reduce the treatment burden associated with hemophilia A,
which currently requires up to 180 injections annually for prophylaxis with
commercially-available Factor VIII 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.

Using the same Fc fusion technology, Biogen Idec and Sobi are also developing a
long-lasting recombinant Factor IX Fc fusion protein (rFIXFc) for the control
and prevention of bleeding episodes and routine prophylaxis in hemophilia B. On
September 26, the companies announced top-line results from B-LONG, a global
pivotal Phase 3 clinical study of rFIXFc in patients with hemophilia B. For more
information on Biogen Idec's hemophilia research programs, visit
www.biogenidechemophilia.com or www.biogenidec.com.

About Hemophilia A
Hemophilia A is a rare, inherited disorder in which the ability of a person's
blood to clot is impaired. Hemophilia A occurs in about one in 5,000 male births
annually and is caused by having substantially reduced or no Factor VIII
protein, which is needed for normal blood clotting. People with hemophilia A
therefore need injections of Factor VIII 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 A. Currently, prophylaxis for
hemophilia A typically requires injections three times per week or every other
day to maintain a sufficient circulating level of clotting factor.

About the Biogen Idec and Sobi Collaboration
Biogen Idec and Sobi are partners in the development and commercialization of
rFIXFc and rFVIIIFc. 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, 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.

About Sobi
Sobi is an international healthcare company dedicated to bringing innovative
therapies and services to improve the lives of rare disease patients. The
product portfolio is primarily focused on inflammation and genetic diseases,
with three late stage biological development projects within hemophilia and
neonatology. Sobi also markets more than 40 products for companies in the
specialty and rare disease space. In 2011, Sobi had revenues of SEK 1.9 billion
and around 500 employees. The share (STO: SOBI) is listed on NASDAQ OMX
Stockholm. More information is available at www.sobi.com.

BIOGEN IDEC CONTACTS
Media Contact:
Jim Baker
Senior Manager, Public Affairs
Ph: +1-781-464-3260
Investor Relations Contact:
Kia Khaleghpour
Director, Investor Relations
Ph: +1-781-464-2442

SWEDISH ORPHAN BIOVITRUM CONTACT
Åsa Stenqvist
Vice President, Head of Communications and Investor Relations (Interim)
Ph: +46 8 697 21 88

Safe Harbor
This press release contains forward-looking statements, including statements
about the development and commercialization 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 the companies' current beliefs and expectations. Drug
development and commercialization involve a high degree of risk. Factors which
could cause actual results to differ materially from the companies' 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 the companies may encounter other unexpected hurdles. For more
detailed information on the risks and uncertainties associated with Biogen
Idec's drug development and commercialization activities, please review the Risk
Factors section of Biogen Idec's 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 the companies assume no
obligation to update any forward-looking statements, whether as a result of new
information, future events or otherwise.

The information above has been published pursuant to the Swedish Securities
Market Act and/or the Financial Instruments Trading Act. The information was
released for public distribution on October 31, 2012 at 1:00 p.m. CET.

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