Corixa announces results of BEXXAR Discussions with the FDA; Corixa to Appeal Recent Complete Review Letter and Will Request Appearance at ODAC Meeting.

Business Editors and Pharmaceutical/Biotechnology Writers

SEATTLE--(BW HealthWire)--May 15, 2002

Corixa Corp. (Nasdaq:CRXA), today announced the results of its recent meeting with the U.S. Food and Drug Administration (FDA) regarding potential commercialization of BEXXAR(R).

In advance of the meeting, the company submitted to the FDA as a part of the BEXXAR Biologics License Application (BLA) detailed responses to the clinical issues raised in the Agency's complete review letter dated March 12, 2002. At the meeting, Corixa and GlaxoSmithKline further articulated their belief that BEXXAR merits approval for the treatment of relapsed, refractory non-Hodgkin's lymphoma patients based on the high level of durable responses observed across multiple clinical studies. The companies contended that this level of persistent, independently confirmed, disease-free survival has not been demonstrated in clinical trials of other products. As a result, the companies believe that BEXXAR does address a medical need that cannot be met via administration of previously approved products in this patient population. Following these discussions, the FDA continued to question the clinical benefit of BEXXAR and suggested that such benefit should be shown in additional, prospective clinical studies.

Following the presentation, and given that a second complete review letter has already been issued, Corixa and the FDA discussed an appropriate process for resolution of the existing differences in opinion. This approach involves a formal request for dispute resolution under the Food and Drug Administration Modernization Act (FDAMA).

As a result of the discussion with the FDA, Corixa will submit a written request to appeal the FDA's position as articulated in the complete review letter dated March 12, 2002 and will further request a presentation of BEXXAR data to the FDA's scientific advisors, the Oncologic Drugs Advisory Committee (ODAC).

Although no new information may be submitted as a part of a request for dispute resolution, if an appeal is granted, Corixa could then provide the FDA with additional information in support of its contention that BEXXAR meets an unmet medical need over and above that manifested by existing products. With respect to Corixa's assertion that BEXXAR provides a level of durable response, the FDA has further provided guidance as to what additional information must be submitted if an appeal is granted. If an appeal is granted, the timing of an ODAC meeting would be dependent upon the receipt and review of additional information submitted in connection with the BLA. However, a presentation before ODAC this year remains a possibility, subject to approval of the appeal.

Although the FDA continues to request additional studies to more carefully assess the true incidence of adverse events and assess for factors that may correlate with an increased incidence of adverse events, following the meeting the FDA also confirmed that based on data submitted to the BLA prior to receipt of the March 12, 2002 complete review letter, the Agency was now able to sufficiently characterize the safety of BEXXAR in order to permit an assessment of net clinical benefit.

"Our meeting with the FDA was productive and we look forward to continuing our work with the Agency in an effort to secure a BEXXAR presentation before an ODAC panel," stated Steven Gillis, Ph.D., chairman and chief executive officer at Corixa. "We intend to provide further updates regarding the formal filing of a request for dispute resolution and the regulatory status of BEXXAR as further developments warrant."

Requests for formal dispute resolution are sent to the appropriate dispute resolution project manager at the Agency. Appeals are then reviewed by the appropriate Center for Biologics Evaluation and Research official as established under the Center's chain of command. A written response from the Agency should be provided within 45 days of receipt of the request for dispute resolution. If additional information is required for the official to make a decision that time period may be extended.

Further information regarding the procedures for dispute resolution is available in the February 2000 FDA Guidance for Industry document, "Formal Dispute Resolution -- Appeals Above the Division Level" and can be accessed at http://www.fda.gov/cber/gdlns/dispute.pdf.

About Corixa

Corixa is a developer of immunotherapeutics with a commitment to treating and preventing autoimmune diseases, cancer and infectious diseases by understanding and directing the immune system. Corixa is focused on immunotherapeutic products and has a broad technology platform enabling both fully integrated vaccine design and the use of its separate, proprietary product components on a standalone basis. Corixa currently has 18 programs in clinical development and 22 programs in preclinical development.

The company partners with numerous developers and marketers of pharmaceuticals, targeting products that are Powered by Corixa(TM) technology with the goal of making its potential products available to patients around the world. Corixa was founded in 1994 and is headquartered in Seattle, with additional operations in Hamilton, Mont., and South San Francisco. For more information, please visit Corixa's Web site at http://www.corixa.com/ or call the company's investor relations information line at 877/4CORIXA (426-7492) or 877/426-7492.

Corixa Forward Looking Statements

Except for the historical information presented, certain matters discussed in this press release are forward-looking statements regarding the regulatory approval of our product candidate, BEXXAR. Forward-looking statements are based on the opinions and estimates of management at the time the statements are made. They are subject to certain risks and uncertainties that could cause actual results to differ materially from any future results, performance or achievements expressed or implied by such statements. Factors that could affect Corixa's actual results include, but are not limited to, the failure of FDA to approve the commercial sale of Bexxar, and the "Factors Affecting Our Operating Results, Our Business and Our Stock Price," described in Corixa's Annual Report on Form 10-K for the year ended Dec. 31, 2001, copies of which are available from Corixa's investor relations department. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this release.