Corixa Announces Initiation of a Phase I Clinical Trial for Its Lung Cancer Vaccine.

Business Editors & Health/Medical Writers

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SEATTLE--(BUSINESS WIRE)--Sept. 17, 2003

Corixa Corp. (Nasdaq:CRXA), a developer of immunotherapeutics, today announced the initiation of a Phase I clinical study to test safety and immune response activity of an investigational vaccine for patients with Non Small Cell Lung Cancer (NSCLC). The trial will be conducted in the United States under a U.S. Food and Drug Administration Investigational New Drug Application (IND) filed by Corixa in late 2002.

Corixa's lung cancer vaccine represents a potential new therapeutic approach to this common and often deadly disease. The vaccine is designed to trigger patient immune responses against an antigen expressed by certain lung cancer cells and, if successful, would be used to prevent disease recurrence in patients following prior treatment. The vaccine contains recombinant plasmid DNA and a recombinant adenovirus, the combination of which may achieve a more substantial immune response to the designated antigen than either component alone. The vaccine formulation has been developed under Corixa's ongoing collaboration with Zambon and the prior collaboration with the pharmaceutical division of Japan Tobacco (JT).

"This is the third Phase I trial we have initiated this year, further demonstrating that we are delivering on our commitment to move validated technology into human clinical trials on a consistent and rapid basis," said Steven Gillis, Ph.D., chairman and chief executive officer of Corixa. "Productive partnerships are an important part of a successful commercialization strategy and we are very encouraged by the results of our collaboration with Zambon and JT. We look forward to the results of this Phase I study."

About the Trial

The Phase I, open-label, dose-escalation trial is enrolling lung cancer patients with Stage IB, IIA or IIB NSCLC. To participate in the study, patients must have undergone surgical resection of their primary cancer within 12 months prior to study entry, have had no other treatment for their cancer and have no evidence of residual or recurrent disease prior to enrollment. Three escalating dose levels will be evaluated as enrolled patients complete each dosing regimen. Recombinant plasmid DNA is being administered using Bioject's Biojector(R) 2000, a reusable needle-free injector powered by a compressed CO2 cartridge.

Corixa holds exclusive rights to all antigens discovered in its lung cancer vaccine program in all countries (including the United States) except those licensed to Zambon Group and JT. Under the terms of an amended license agreement announced in January 2003, JT holds an exclusive license to this vaccine candidate for development and commercialization in Japan, and Zambon retains exclusive rights to lung cancer vaccine products in Europe, the countries of the former Soviet Union, Argentina, Brazil and Colombia. Corixa shares commercialization rights with Zambon on a co-exclusive basis in China.

About Non Small Cell Lung Cancer

According to the American Cancer Society, approximately 171,000 new cases of lung cancer will be diagnosed in the United States and more than 157,000 Americans will die of the disease in 2003. Lung cancer is the leading cause of cancer death for men and women. More people die of lung cancer than of colon, breast and prostate cancers combined.

Globally, NSCLC is the most common type of lung cancer, accounting for almost 80 percent of lung cancers. NSCLC affects more than one million men and women worldwide each year and is most often characterized by a poor survival rate.

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, non-Hodgkin's lymphoma, 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, Mont., and South San Francisco. For more information, please visit Corixa's Web site at http://www.corixa.com/.

About Zambon Group

Zambon Group is a pharmaceutical and chemical company with a reputation for inventive and innovative thinking, flexibility and customer focus. Zambon Group has grown to become a leading multinational firm with about 2,500 employees in 16 countries and 438 million euro in consolidated sales. Operating directly in three continents -- Europe, South America and Asia -- Zambon Group is a multicultural group with close links to its local markets and the international research communities alike. These strengths, combined with diversified research, product and distribution channel strategies, ensure that Zambon Group consistently outperforms its competitors and the market. Zambon is proud of its rich portfolio of ground-breaking products and dosage forms, which improves the quality of life of thousands of people world-wide. For more information, visit http://www.zambongroup.com/.

Corixa Forward-Looking Statements

This press release contains forward-looking statements, including statements about the clinical development of a potential lung cancer vaccine, statements about the potential efficacy of lung cancer vaccines in inhibiting cancer growth, 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, possible delays or failure by Corixa to develop and/or commercialize a potential vaccine for lung cancer, potential inefficacy of lung cancer vaccines in treating lung cancer, and the "Factors Affecting Our Operating Results, Our Business and Our Stock Price," described in Corixa's Quarterly Report on Form 10-Q for the quarter ended June 30, 2003, 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.