IDEC Pharmaceuticals Begins Phase II Study in Immune Thrombocytopenic Purpura (ITP) With Its Humanized Antibody, IDEC-131

(BW HealthWire) — IDEC Pharmaceuticals (Nasdaq:IDPH) today announced that it has initiated a Phase II clinical trial with its investigational agent, IDEC-131, a humanized anti-CD154 (anti-CD40L) monoclonal antibody. The multiple-center, multiple-dose study will evaluate the potential clinical activity and safety of this investigational agent in patients with chronic, refractory immune thrombocytopenic purpura (ITP), a blood disorder characterized by low platelet counts which can pose a significant risk of life-threatening bleeding.

“We believe that IDEC-131 has potential benefit as a therapeutic agent for diseases such as ITP that are characterized by the production of autoantibodies,” said Mark Totoritis, M.D., senior director, autoimmmune and inflammatory diseases. “In fact, preliminary evidence of improvement in platelet counts has been observed in an ongoing clinical investigation of IDEC-131 in a small number of ITP patients at Weill Medical College of Cornell University.”

IDEC-131 targets a key pathway in the immune system — the CD154-CD40 pathway — that involves collaboration between T cells and B cells, as well as other antigen-presenting cells. Therefore, this antibody therapeutic may have application in diseases that are caused by overactive T cells and in those that are characterized by excessive autoantibody production by B cells.

IDEC-131 is based on technology that IDEC licensed from Dartmouth University, where researchers have demonstrated the beneficial effects of the anti-CD154 antibody in animal models of autoimmunity.

Eisai Company, Ltd. has licensed the commercial rights of IDEC-131 in Europe and Asia. IDEC retains exclusive rights outside of Europe and Asia.

IDEC Pharmaceuticals focuses on the commercialization and development of targeted therapies for the treatment of cancer and autoimmune diseases. IDEC’s antibody products act chiefly through immune system mechanisms, exerting their effect by binding to specific, readily targeted immune cells in the patient’s blood or lymphatic systems.

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The statements made in this press release contain certain forward-looking statements that involve a number of risks and uncertainties. Actual events or results may differ from IDEC’s expectations. For example, 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 and the risk factors listed from time to time in IDEC’s SEC filings including but not limited to its Annual Report on Form 10-K for the year ended December 31, 1999 and Form 10-Q for the quarter ended September 30, 2000, may affect the actual results achieved by IDEC. These forward-looking statements represent the company’s judgment as of the date of this release. The company disclaims, however, any intent or obligation to update these forward-looking statements.

IDEC Pharmaceuticals is registered U.S. trademarks of the company. The company’s headquarters is located at 3030 Callan Road, San Diego, CA 92121.

CONTACT: IDEC Pharmaceuticals