Corixa and GlaxoSmithKline Announce FDA Acceptance of Supplemental Biologics License Application for Expanded Use of BEXXAR; FDA Response Expected by January 2005.

SEATTLE & PHILADELPHIA -- Corixa Corporation (Nasdaq:CRXA), a developer of immunotherapeutics, and GlaxoSmithKline (NYSE:GSK) today announced that the U.S. Food and Drug Administration (FDA) has accepted Corixa's supplemental Biologics License Application (sBLA) for expanded use of the BEXXAR(R) therapeutic regimen (Tositumomab and Iodine I 131 Tositumomab). The FDA also has granted priority review status to the BEXXAR BLA. As a result, the Companies expect the FDA to complete its review of the BEXXAR sBLA by January 2005.

Corixa has requested accelerated approval for the expanded use of BEXXAR in treatment of patients with relapsed or refractory low-grade, follicular or transformed CD20-positive non-Hodgkin's lymphoma (NHL) whose disease has relapsed following chemotherapy. The BEXXAR therapeutic regimen is currently indicated for the treatment of patients with CD20-positive, follicular NHL, with and without transformation, whose disease is refractory to the antibody treatment Rituximab and has relapsed following chemotherapy.

"The filing of the supplemental BLA demonstrates our continued commitment to the research and development of BEXXAR for the treatment of NHL," said Steven Gillis, Ph.D., chairman and chief executive officer of Corixa. "We look forward to working with the FDA to expeditiously complete the review process for BEXXAR in this expanded patient population."

About the BEXXAR Therapeutic Regimen

BEXXAR pairs the targeting ability of a monoclonal antibody (Tositumomab) and the therapeutic potential of radiation (Iodine-131). Combined, these agents form a radiolabeled monoclonal antibody regimen that is able to bind to the target antigen CD20 found on B cells, including normal cells and those that become cancerous in non-Hodgkin's lymphoma, thereby delivering the dose of radiation. BEXXAR, which is given in four visits over one to two weeks, is specifically dosed based on an individual's drug clearance rate, allowing the delivery of a predetermined amount of radiation to each patient.

The BEXXAR therapeutic regimen has been studied for over 13 years. In a multicenter, single-arm, clinical trial in 40 patients who had received an average of four prior chemotherapies and who had Rituximab-refractory disease (N=35), 63 percent (22 of 35) responded to BEXXAR. The median duration of response was 25 months. The results of this study were supported by demonstration of durable objective responses in four single-arm studies enrolling 190 patients evaluable for efficacy with Rituximab-naive, follicular non-Hodgkin's lymphoma, with or without transformation, who had relapsed following or were refractory to chemotherapy. Determination of clinical benefit of the BEXXAR therapeutic regimen was based on evidence of durable responses without evidence of an effect on survival.

The BEXXAR therapeutic regimen is not indicated for the initial treatment of patients with CD20-positive non-Hodgkin's lymphoma. The BEXXAR therapeutic regimen is intended as a single course of treatment. The safety of multiple courses of the BEXXAR therapeutic regimen, or combination of this regimen with other forms of irradiation or chemotherapy, has not been evaluated.

BEXXAR is not for everyone. Patients who are pregnant or allergic to any components of the regimen should not receive BEXXAR. Treatment with BEXXAR resulted in very low blood counts in the majority of patients, which could be serious, for an extended period of time (about a month). Infections occurred in almost half the patients, bleeding in one of eight patients, and treatment with supportive care in about one of four patients. Allergic reactions, including anaphylaxis, which may be severe, have occurred in patients receiving BEXXAR. Other less severe reactions during or following the infusion have included fever, chills, sweating, nausea, low blood pressure, shortness of breath and trouble breathing. Patients may also experience weakness, fever, nausea, increased cough, infection, pain, chills, rash or headache. There is a risk of hypothyroidism following the administration of BEXXAR. Administration of BEXXAR resulted in the development of antibodies to the mouse antibody (called HAMA). Certain cancer therapies including BEXXAR have been associated with the development of a second type of blood cancer and solid tumors. Thirty-two cases (3.2 percent) of myelodysplastic syndrome (a type of pre-leukemia) and/or leukemia and 52 cases of secondary tumors were reported in 995 patients enrolled in BEXXAR studies. After being treated with BEXXAR, less than five percent of patients suffered hair loss or developed severe nausea, vomiting or mucositis (sores in the mouth or gastrointestinal tract). Healthcare providers must be specifically trained to administer BEXXAR.

BEXXAR was developed by Corixa Corporation and is co-marketed in the United States by Corixa Corporation and GlaxoSmithKline. Additional information about the BEXXAR therapeutic regimen, including complete prescribing information, may be obtained by calling 877-423-9927 (4BEXXAR) or visiting http://www.bexxar.com.

About Corixa

Corixa is a biopharmaceutical company developing oncology and immunology products that manage human diseases. On June 30, 2003, Corixa announced that the FDA approved BEXXAR 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, Mont., and South San Francisco. For more information, please visit Corixa's Web site at http://www.corixa.com.

About GlaxoSmithKline

GlaxoSmithKline (NYSE:GSK) is one of the world's leading research-based pharmaceutical and healthcare companies. GlaxoSmithKline is committed to improving the quality of human life by enabling cancer patients to do more, feel better and live longer. For more information, visit www.gsk.com.

Corixa Forward-Looking Statements

This press release contains forward-looking statements, including statements regarding the commercial potential for BEXXAR and 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 "Factors Affecting Our Operating Results, Our Business and Our Stock Price," described in our Quarterly Report on Form 10-Q for the quarter ended June 30, 2004, 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.