Corixa and Apovia AG Announce Collaboration Agreement for RC-529 Adjuvant.

Business Editors & Health/Medical Writers

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SEATTLE & MARTINSRIED, Germany--(BUSINESS WIRE)--Aug. 14, 2003

Corixa Corp. (Nasdaq:CRXA) and Apovia AG today announced a research, development and commercialization agreement for Corixa's synthetic adjuvant, RC-529. The multiyear agreement grants Apovia commercial rights to RC-529 for use in an undisclosed therapeutic vaccine. Both companies will equally share research, development and commercialization costs, as well as any potential product revenue.

"RC-529 adjuvant is a synthetic adjuvant that has been shown to stimulate immune responses to multiple vaccine antigen formulations both in animal models and in man," said Steven Gillis, Ph.D., chairman and chief executive officer at Corixa. "We look forward to continuing the development of our adjuvant portfolio in a variety of clinical indications and, in particular, to working with Apovia on the development of therapeutic vaccines."

"Partnership opportunities such as this represent an important part of Apovia's future growth strategy and we are excited to work with Corixa," said Martin Steiner, chief executive officer at Apovia. "After evaluating many different adjuvant concepts, we believe that the performance profile of Corixa's RC-529 adjuvant is ideally suited for our vaccine platform and look forward to testing the combination in the clinic in the near future," commented George B. Thornton, executive vice president of research and development at Apovia.

Corixa's RC-529 Adjuvant

RC-529 is the lead adjuvant compound from Corixa's AGP chemical library. As a totally synthetic molecule, it can be formulated for a variety of applications including intranasal and pulmonary vaccines, and is capable of producing both mucosal and systemic immunity. RC-529 is currently under evaluation with a number of vaccines.

About Apovia

Apovia is a biopharmaceutical company focused on the prevention and treatment of infectious diseases through vaccines based on its proprietary modified hepatitis B core vaccine carrier platform. The Company conducts research at its headquarters in Martinsried, Germany and at its subsidiary Apovia Inc. in San Diego, California, and produces clinical trial material at its pilot GMP manufacturing facility in Coralville, Iowa. Apovia's product candidates under development include vaccines against malaria, chronic hepatitis B infection, influenza and otitis media. For more information, please visit Apovia's web site at http://www.apovia.com/.

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. On June 30, 2003, Corixa announced that the FDA approved BEXXAR(R) for the treatment of patients with CD20 positive, follicular, NHL, with and without transformation, whose disease is refractory to Rituximab and has relapsed following chemotherapy.

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. In addition to BEXXAR, Corixa currently has multiple programs in clinical development, including several product candidates that have advanced to and through late stage clinical trials. 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, Montana and South San Francisco. For more information, please visit Corixa's Web site at http://www.corixa.com/.

Corixa Forward-Looking Statements

This press release contains forward-looking statements, including statements about our plans, objectives, intentions and expectations. 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 risk that the collaboration with Apovia does not result in any clinically safe or effective products or commercial products, and the "Important Factors That May Affect Our Business, Our Results of Operations and Our Stock Price," described in our Quarterly Report on Form 10-Q for the quarter ended June 30, 2003, copies of which are available from our 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.