IDEC Pharmaceuticals Receives Notification of FDA Acceptance of Resubmission to the ZEVALIN Biologics License Application

(BW HealthWire) — IDEC Pharmaceuticals Corporation (Nasdaq: IDPH) today announced that the U.S. Food and Drug Administration (FDA) has formally acknowledged receipt of the July 9, 2001 resubmission to the Biologics License Application (BLA) for ZEVALIN(TM) (Ibritumomab Tiuxetan) and has characterized the resubmission as complete.

The Agency noted that IDEC’s resubmission of its license application was a Class II response to its Complete Review Letter of May 3, 2001. As a Class II response under FDA guidelines, the FDA may approve, not approve, or raise additional questions regarding the BLA at any time within six months from the resubmission date.

As previously noted on July 23, 2001, IDEC announced that ZEVALIN, an investigational agent for the treatment of relapsed or refractory, low grade, follicular, CD20-positive transformed, B-cell non-Hodgkin’s lymphoma (NHL) and Rituximab-refractory follicular NHL, will be reviewed by the Oncologic Drugs Advisory Committee (ODAC) of the FDA on September 11, 2001.

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 system. For a menu of IDEC’s current news 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:

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, such as ZEVALIN, 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, 2000 and Form 10-Q for the quarter ended March 31, 2001, 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 a registered U.S. trademark of the company. ZEVALIN is a trademark of the company. The company’s headquarters are located at 3030 Callan Road, San Diego, CA 92121.

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CONTACT: IDEC Pharmaceuticals Corporation, San Diego