FDA Issues ``Completed Review'' Letter On Expanded Studies of Rituxan -- Rituximab --.

Business Editors/Health & Medical Writers

BIOWIRE2K

SAN DIEGO--(BW HealthWire)--Sept. 27, 2000

IDEC Pharmaceuticals Corporation (Nasdaq:IDPH) announced today that it had received a "completed review" letter from the U.S. Food and Drug Administration (FDA) indicating that it has completed review of a supplemental Biological License Application (sBLA) for Rituxan(R) (Rituximab).

IDEC submitted the sBLA in late 1999 based on studies in non-Hodgkin's lymphoma (NHL) of Rituxan: 1) treatment of patients with bulky disease, 2) provide for dosing of up to eight weekly doses per treatment, and 3) multiple courses of treatment.

During the review process, IDEC provided the FDA with proposed revisions and additions to the Rituxan Package Insert (PI). In its "completed review" letter, the FDA commented only on the details of the PI.

Based on the FDA's comments, IDEC will begin discussions with the FDA with the objective of finalizing revisions to the Rituxan PI.

Originally approved by the FDA in November 1997, Rituxan is indicated for the treatment of patients with relapsed or refractory, low grade or follicular, CD20 positive, B-cell NHL. Rituxan was discovered by IDEC and is jointly developed by IDEC, Genentech Inc., F. Hoffmann-La Roche Ltd. of Switzerland and Zenyaku Kogyo Co. Ltd. of Japan. Roche has marketing rights to Rituximab outside of the United States and Japan. Worldwide, Rituxan is approved for use in 55 countries.

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. IDEC is headquartered in San Diego, California, and is traded on the NASDAQ National Market System under the stock symbol, IDPH.

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, achievement of product development milestone events and future product sales, the timing, success and cost of product launches and clinical studies, the timing, acceptability and review periods of regulatory filings, the timing of and ability to obtain regulatory approval of products, the level of manufacturing performance and performance of our suppliers, 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 June 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 and Rituxan are registered U.S. trademarks of the company. The company's headquarters is located at 3030 Callan Road, San Diego, CA 92121.

IDEC Pharmaceuticals' press releases are available at no charge through Business Wire's News on Demand Plus. For a menu of IDEC's current press releases and quarterly reports or to retrieve a specific release, call 888/329-2309. On the Internet, check the News Center at IDEC's website http//www.idecpharm.com.