Biogen Idec to Acquire Syntonix.

CAMBRIDGE, Mass. & WALTHAM, Mass. -- Biogen Idec (NASDAQ: BIIB) and Syntonix Pharmaceuticals today announced that the companies have signed a definitive agreement for the acquisition of Syntonix by Biogen Idec. Syntonix, a privately held biopharmaceutical company focused on discovering and developing long-acting therapeutic products to improve treatment regimens for chronic diseases, has multiple pre-clinical programs in hemophilia.

Syntonix uses proprietary technologies to harness the human body's natural pathways for protecting antibodies against premature destruction and for transporting antibodies across cell barriers such as those in the lungs. These technologies may enhance the delivery of biopharmaceuticals through less frequent injections or by enabling pulmonary delivery.

Syntonix's lead product, FIX:Fc, is a proprietary long-acting factor IX product for the treatment of hemophilia B. It has the potential to reduce the frequency of intravenous injections required for disease management. Syntonix is expected to file an investigational new drug application with the Food and Drug Administration for FIX:Fc in 2007.

"With this transaction, we continue to deliver on our strategic initiative to enhance our pipeline and expand into additional specialized markets," said James C. Mullen, Biogen Idec's President and Chief Executive Officer (CEO). "Syntonix brings promising science and technology to areas of unmet medical need such as hemophilia, and we look forward to building on their expertise with Biogen Idec's global development, manufacturing, and commercial capabilities."

"In pursuing next steps for Syntonix, joining forces with Biogen Idec was the best option for all stakeholders, including - over the long-term - patients," said John W. Ripple, CEO of Syntonix. "As a global leader in biomanufacturing and serving niche markets, Biogen Idec is well-poised to deliver on the promise of hemophilia therapies that require less frequent dosing."

The transaction is expected to close in the first quarter of 2007. Upon completion, Biogen Idec will acquire all of the issued and outstanding shares of the capital stock of Syntonix for $40 million, payable at closing, and potential additional payments of up to $80 million upon the achievement of certain development milestones.

Contingent on the closing of the acquisition, Biogen Idec plans to maintain Syntonix's 25,000 square-foot facility in Waltham, MA for the continuing operation of Syntonix programs. The transaction, which has been approved by the boards of directors of both companies, is subject to customary closing conditions.

About Syntonix's Hemophilia Programs and Technology Platforms

FIX:Fc is being developed for the treatment of hemophilia B in a strategic alliance with Biovitrum AB of Sweden with the companies sharing equally the costs and profits of development and commercialization. After regulatory approval, Syntonix is responsible for marketing FIX:Fc in North America and Biovitrum is responsible for marketing FIX:Fc in Europe, Russia, and the Middle East.

Syntonix is pursuing other early-stage programs, including a long-acting factor VIII program, with the potential to improve the treatment of hemophilia A. In developing novel and improved treatments, the company uses propriety technology, including the SynFusion[TM] and Transceptor[TM] platforms.

SynFusion drugs are based on proprietary Fc-fusion technology to create long-acting biopharmaceuticals with reduced dosing frequencies. Specifically, the SynFusion technology links a single copy of the drug to the Fc region on an antibody to optimize the pharmacokinetic and pharmacodynamic properties of the biopharmaceutical and extending its circulating half-life.

Transceptor is a proprietary technology that enables pulmonary delivery of a SynFusion or Fc-fusion drug. The natural FcRn pathway transports antibodies and Fc-fusion drugs across the epithelial cell barrier in the lungs.

About Hemophilia

Hemophilia is a rare, inherited bleeding disorder that is caused by mutations that impair or eliminate the production of essential clotting factors naturally found in the blood. Hemophilia B, caused by mutations in the factor IX gene, affects approximately 3,600 people in the Unites States. Hemophilia A, caused by mutations in the factor VIII gene, affects approximately 14,500 people in the U.S. Both forms of hemophilia are characterized by spontaneous or prolonged bleeding for which there is no cure.

Today a majority of hemophilia patients are treated with recombinant-derived factor VIII and IX products. Increasingly, younger patients are prescribed prophylaxis regimens with these products to prevent bleeding, rather than receiving treatment at the time of a bleed ("on-demand"). Long-term studies have demonstrated that maintaining a better circulating level of coagulation factor by infusing patients two or three times a week greatly reduces progressive joint deterioration commonly seen in hemophilia patients as a result of the bleeding.

About Syntonix

Syntonix is developing next generation biopharmaceuticals that enable better treatment options for patients with devastating chronic diseases such as hemophilia, anemia, and autoimmune disorders. The company applies its core technologies to develop long-acting SynFusion drugs that may be inhaled or injected less frequently. The resulting proteins, peptides and antibodies are being commercialized through internal development programs and collaborations with biotechnology and pharmaceutical partners. More information is available at www.syntnx.com.

About Biogen Idec

Biogen Idec creates new standards of care in oncology, neurology and immunology. As a global leader in the development, manufacturing, and commercialization of novel therapies, Biogen Idec transforms scientific discoveries into advances in human healthcare. 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 regarding the acquisition of Syntonix Pharmaceuticals and the development of FIX:Fc. These statements are based on the companies' current beliefs and expectations. Drug development involves 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, that regulatory authorities may require additional information, further studies, or may fail to approve the drug, or that the company may encounter other unexpected hurdles. For more detailed information on the risks and uncertainties associated with Biogen Idec's drug development and other activities, see the periodic reports of Biogen Idec Inc. filed with the Securities and Exchange Commission. Biogen Idec assumes no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.