PRESS RELEASE: Biogen Idec and Neurimmune Announce $380M Alliance to Develop Treatments for Alzheimer's Diseases

Biogen Idec and Neurimmune Announce $380M Alliance to Develop Treatments for Alzheimer's Diseases

Cambridge, MA and Zürich, Switzerland, November 20, 2007 – Biogen Idec and Neurimmune Therapeutics AG today announced they have entered into an agreement for the worldwide development and commercialization of novel, fully human antibodies for the treatment of Alzheimer’s disease (AD). The alliance will focus on the development of antibodies that bind to amyloid beta (Ab), a pathogenic molecule thought to cause neurodegeneration and loss of cognitive function in AD patients. Currently there are no therapies for AD approved to slow or stop the progression of the disease.

Neurimmune will conduct research to identify potential therapeutic antibodies using the company’s Reverse Translational Medicine (RTM) platform. Biogen Idec will be responsible for the development and commercialization of all products. Neurimmune could receive an aggregate of $380M in upfront and success-based milestone payments, as well as a royalty on net sales of any products.

“Biogen Idec has the manufacturing, development and commercialization capabilities to leverage our discovery and technology expertise. With their extraordinary experience in the development of biopharmaceuticals as well as their deep history in neuroscience, Biogen Idec is the perfect partner for Neurimmune,” said Edward Stuart, PhD, Chief Executive Officer of Neurimmune. “Our RTM platform is well suited to the identification of novel, safe immunotherapies for the treatment of human disease and we are particularly proud to have entered into this deal less than one year after the founding of the company.”

“Biogen Idec has built a leading position in the development and commercialization of treatments for neurological diseases such as multiple sclerosis. This alliance with Neurimmune enables us to be at the forefront of applied Alzheimer’s research, with access to an outstanding team of researchers and a remarkable technology platform,” said Alfred Sandrock, MD, PhD, Senior Vice President, Neurology Research and Development, Biogen Idec.

Alzheimer’s disease is the most prevalent age-related neurodegenerative disease affecting more than 15 million patients worldwide. Alzheimer’s disease patients experience the progressive loss of cognitive functions, particularly those related to memory, followed by death eight to 15 years following a progressive decline in their disease. The pathology of Alzheimer’s disease is characterized by distinctive features including the deposition of Ab in the form of senile plaques and the loss of specific neuronal populations in the brain.

Professor Roger Nitsch, a founder of Neurimmune and head of the Division of Psychiatric Research at the University of Zurich commented, “We have realized our aim of bringing our RTM platform to this advanced stage in such a short time period. We look forward to the advancement of these products for the benefit of Alzheimer’s disease patients.”

About Neurimmune Therapeutics AG

Neurimmune Therapeutics AG is an emerging leader in neurodegenerative disease drug development. Based on its proprietary Reverse Translational Medicine (RTM) platform, the company is focusing on the goal to develop a pipeline of safe and potent immunotherapies that circumvent the potential side effects of active vaccination. Neurimmune Therapeutics started operations in 2007 and is a spin-off of the University of Zürich, Switzerland. The company is fully financed by its directors and management. Dr. Karsten Henco is its Chairman, co-founder and lead investor. For additional information, please visit www.neurimmune.com [1].

About Biogen Idec

Biogen Idec creates new standards of care in therapeutic areas with high unmet medical needs. Founded in 1978, Biogen Idec is a global leader in the discovery, development, manufacturing, and commercialization of innovative therapies. Patients in more than 90 countries benefit from Biogen Idec's significant products that address diseases such as lymphoma, multiple sclerosis, and rheumatoid arthritis. The company’s corporate headquarters are in Cambridge, MA and all international functions and operations are coordinated from its International Headquarters in Zug, Switzerland. For press releases and additional information about the company, please visit, www.biogenidec.com [2].

Biogen Idec Safe Harbor This press release contains forward-looking statements regarding the agreement with Neurimmune Therapeutics AG and the development of anti-Alzheimer’s antibodies. These statements are based on the companies' current beliefs and expectations. Drug development involves a high degree of risk. Only a small number of research and development programs result in commercialization of a product. Factors which could cause actual results to differ materially from Biogen Idec's current expectations include the risk that the company may not be able to demonstrate the safety and efficacy of such antibodies at each stage of the clinical trial process; technical difficulties relating to the manufacture of such antibodies may be encountered; the company may not be able to meet applicable regulatory standards or regulatory authorities may fail to approve such antibodies; and 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 Item 1A entitled "Risk Factors" in Biogen Idec's quarterly report on Form 10-Q for the fiscal quarter ended September 30, 2007 that was filed with the Securities and Exchange Commission on October 23, 2007, as well as other periodic and current reports of Biogen Idec 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.