IDEC Pharmaceuticals and Biogen Announce Oncology Collaboration.

Business Editors & Health/Medical Writers

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SAN DIEGO & CAMBRIDGE, Mass.--(BUSINESS WIRE)--Jan. 30, 2003

IDEC Pharmaceuticals Corporation (Nasdaq: IDPH) and Biogen, Inc. (Nasdaq:BGEN) today announced plans to co-develop three oncology therapeutics from Biogen's pipeline of early-stage development candidates.

The collaboration leverages the companies' world-class capabilities in their respective areas of discovery research, development, and manufacturing. By working together, the companies expect these promising new therapeutics for patients with cancer to move forward more rapidly.

The three oncology product candidates are:

-- An anti-lymphotoxin beta receptor (LTBR) monoclonal antibody. LTBR is a member of the TNF superfamily of cytokines. The activation of LTBR has been demonstrated to inhibit tumor growth in animal models. An agonist antibody against this target has been generated.

-- An anti-CRIPTO monoclonal antibody. Cripto is a novel cell surface signaling molecule that is over expressed in a multitude of solid tumors including breast, colon and lung.

-- An interferon beta (INF-b) gene delivery product for glioma that is in Phase I. INF-b gene delivery has exhibited direct and indirect anti-tumor activity and has the potential to treat a broad range of tumors with high unmet medical need.

"This alliance with Biogen could significantly expand IDEC's core business in targeted therapies for the treatment of cancers," said William H. Rastetter, IDEC's Chairman and Chief Executive Officer. "Each of these oncology programs is complementary to our internal programs for targeting solid tumor indications such as colon, prostate and ovarian carcinomas."

James C. Mullen, Biogen's Chairman and Chief Executive Officer said, "Biogen is very pleased to enter into this partnership with IDEC, a biotechnology leader in the development and commercialization of oncology products. The collaboration validates the productivity and promise of Biogen's discovery research organization, but more importantly will accelerate the development of these unique therapies."

Lazard Freres & Co. LLC served as an advisor to Biogen in the development of strategic options related to the company's oncology program.

About IDEC Pharmaceuticals

IDEC Pharmaceuticals Corporation is a leader in the discovery, development, and commercialization of targeted immunotherapies for the treatment of cancer and autoimmune diseases. IDEC discovered and developed the first commercially available radioimmunotherapy product (Zevalin(R)) approved in the United States, which is used to treat certain non-Hodgkin's lymphomas. IDEC also discovered, and with co-promotion partner Genentech, Inc., developed the first monoclonal antibody product (Rituxan(R)) approved in the United States for the treatment of cancer. Rituxan is approved in over 70 countries worldwide and is also used to treat various types of non-Hodgkin's lymphomas. IDEC is a San Diego based, integrated biopharmaceutical company with multiple products in clinical stage development and strategic alliances involving a variety of research platforms. For press releases and additional information about the company, please visit http://www.idecpharm.com.

About Biogen

Biogen is the world's oldest independent biotechnology company and a leader in biologics research, development and manufacturing. A pioneer in leading edge research in immunology, neurobiology and oncology, Biogen brings novel therapies to improve patients' lives around the world through its global marketing capabilities. For press releases and additional information about the company, please visit http://www.biogen.com.

The statements made in this press release contain certain forward-looking statements that involve a number of risks and uncertainties. Reference is made in particular to statements regarding the Companies' expectations regarding the development and therapeutic benefit of the three oncology candidates, and IDEC's expectations regarding the impact of the collaboration on its core business. Actual events or results may differ from the Companies' expectations. Drug development involves a high degree of risk. Success in animal work or early stage clinical trials does not ensure that later stage or larger scale clinical trials will be successful. In addition, the timing, success and cost of preclinical research and clinical studies, the timing, acceptability and review periods for regulatory filings, the timing of and ability to obtain regulatory approval of products, the achievement of future product sales, the level of manufacturing performance, issues that may arise with respect to the intellectual property position of the candidates, and the risk factors listed from time to time in the parties' periodic filings with the SEC, including but not limited to the Companies' Annual Reports on Form 10-K for the year ended December 31, 2001 and Form 10-Q's for the quarter ended September 30, 2002, may affect the actual results achieved by the Companies. These forward-looking statements represent the Companies judgment as of the date of this release. The Companies disclaim, however, any intent or obligation to update these forward-looking statements.