Corporate Announcements

Astellas to Acquire AMEVIVE®

Acquisition of psoriasis product deepens Astellas' commitment to dermatology franchise and the Canadian psoriasis community

Markham, Ontario, April 3, 2006 — Astellas Pharma Canada, Inc. today announced that U.S. affiliate company Astellas US LLC has concluded an agreement to purchase the worldwide rights to AMEVIVE(R) (alefacept) as of March 31, 2006. AMEVIVE is a biologic anti-inflammatory compound used in the treatment of moderate-to-severe plaque psoriasis.

Under the terms of the agreement, Astellas would acquire the worldwide rights to AMEVIVE in all indications from Biogen Idec. Biogen Idec would continue to manufacture AMEVIVE and supply the product to Astellas. The parties anticipate closing the deal as early as mid-April.

"AMEVIVE was the first biological treatment approved in Canada for moderate-to-severe plaque psoriasis. The acquisition of this well established product not only strengthens our dermatology franchise but also provides Astellas with an important opportunity to offer Canadian dermatologists an effective treatment option for a very difficult to treat skin disease," said Hiromu Ozaki, President of Astellas Pharma Canada.

In Canada, all commercial responsibility for AMEVIVE will be transferred to Astellas Pharma Canada, Inc. Biogen Idec Canada Inc. will continue to provide sales and marketing support for AMEVIVE during the transitional period.

About AMEVIVE
AMEVIVE is the first biologic approved by Health Canada for the treatment of moderate-to-severe chronic plaque psoriasis in patients who are candidates for systemic therapy or phototherapy. AMEVIVE is a prescription medication that is injected (by a physician, a nurse or the patient) once a week, for a total of 12 doses (intermittent re-treatment with subsequent courses may be initiated if appropriate). AMEVIVE was approved by Health Canada in October 2004. The most serious adverse reactions found in clinical trials were: lymphopenia, malignancies, serious infections requiring hospitalization and hypersensitivity. AMEVIVE is contraindicated in patients infected with HIV and in patients who are allergic to any of the components of AMEVIVE. For more information about AMEVIVE, including prescribing information call 1-877-AMEVIVE (263-8483).

About Chronic Plaque Psoriasis
Psoriasis is a chronic but treatable autoimmune skin disease. Roughly two per cent of the world's population has psoriasis. In Canada, psoriasis affects one million people, and about one-third have moderate-to-severe chronic plaque psoriasis. While psoriasis is not typically life threatening, it can greatly affect an individual's appearance, self-esteem, interpersonal relationships and overall quality of life. Chronic plaque psoriasis can develop anywhere on the skin, though it usually appears on the scalp, knees, elbows, and torso.

About Astellas Canada
Astellas Pharma Canada, Inc. currently sells Protopic, the first steroid-free topical treatment for atopic dermatitis (eczema). It is one of the Astellas Group of companies in North America and a subsidiary of Astellas Pharma Inc., located in Tokyo. The company is dedicated to improving the health of people around the world through the provision of innovative and reliable pharmaceutical products. Astellas was formed in April 2005, through the merger of Fujisawa Pharmaceutical Co., Ltd. and Yamanouchi Pharmaceutical Co., Ltd. The organization is committed to becoming a global mega pharmaceutical company by combining outstanding R&D and marketing capabilities and continuing to grow in the world pharmaceutical market. Additional corporate and product information is available at www.astellas.com/ca.

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 press releases and additional information about the company, please visit www.biogenidec.com.