Panbio Purchases Intellectual Property from Corixa for Detecting Tick Borne Diseases.

SEATTLE & BRISBANE, Australia -- Australian-based international medical diagnostics company Panbio Limited, listed on the Australian Stock Exchange (ASX:PBO) and Corixa Corporation (Nasdaq:CRXA), a developer of immunotherapeutics, announced today that Panbio has signed an agreement to acquire intellectual property from Corixa that would assist in the development of new assays for the diagnosis of the tick borne diseases, Ehrlichiosis and Babesiosis.

Under terms of the agreement, Corixa will receive an undisclosed up-front payment, annual maintenance payments and royalties on future product sales. The agreement will also transfer to Panbio a portfolio of unique recombinant proteins that are specific to these infections. Panbio will be responsible for all product development and commercialization.

Panbio Senior Vice President for US Operations Carl Stubbings said the agreement with Corixa would enable the company to undertake the development of a range of tests for this important group of emerging diseases in the United States.

"The proteins that Corixa has patented have shown very encouraging results in initial research, and will offer an opportunity to quickly bring to market a range of tests to enable public and private diagnostic laboratories to easily test for these diseases," he said.

"Like West Nile, this is an example of Panbio quickly responding to a request from our customers for a reliable test to an emerging infectious disease."

Panbio estimates the total market for diagnostic testing for Ehrlichiosis and Babesiosis is approximately US $5 million, with strong evidence that the level and demand for testing is increasing. In addition, recognition of Babesiosis in blood donors in the United States has raised the possibility of blood donor testing in the future.

"We are pleased to place our tick-borne disease assets with Panbio," said David Persing, MD, PhD, chief scientific officer at Corixa. "The tests Panbio plans to develop could prove to be very useful in evaluating patients with non-specific febrile illnesses from areas that are endemic for Lyme disease and other tick-borne diseases. Establishing an accurate diagnosis of infection or co-infection in such patients is the first step in their effective therapeutic management."

Bacteria in the genus Ehrlichia or Anaplasma cause human ehrlichioses. Spread by ticks, these bacteria grow inside the white blood cells of humans and other animals. An infection with Anaplasma phagocytophilum is known as human granulocytic ehrlichiosis or anaplasmosis (HGE). The same Ixodes tick that carries Lyme disease spreads HGE and the geographic distribution of these two diseases is similar. The ticks also feed on deer, elk, and other animals, which have contributed to the expansion of the range of infection.

Human ehrlichial diseases outside of Asia were first identified in the mid-1980s. Their true incidence and geographic distribution are being documented while increased awareness and testing have led to rising numbers of reported cases in the U.S. and other parts of the world. While some ehrlichia infections are not apparent, they may cause an acute febrile disease of varying severity, with an estimated fatality incidence of 2% to 3%.

Prompt treatment with antibiotics can reduce the impact of the illness. Major risk groups are the very young, the elderly and immunocompromised individuals. Standard serological techniques have been useful, but with increased testing, there is an expanded need for automated processing of large numbers of patient specimens.

Babesiosis is caused by a single-celled blood parasite that is spread by the same tick species as is HGE. With a worldwide distribution, babesia infections also have a broad range of outcomes, with immunosuppressed and elderly individuals being most at risk of severe disease. Although the parasite may be identified in blood smears, diagnosis by serological methods is important in instances of low parasitemia. In addition to infection by tick bites, the transmission of babesia infection by blood transfusion is becoming a recognized threat.

About Panbio

Panbio is an international diagnostics company headquartered in Brisbane, Australia. With operations in Brisbane and Columbia, Maryland U.S.A., the company develops, manufactures and markets diagnostic tests primarily for the detection of antibodies against agents of infectious disease. PANBIO products are used in the diagnosis of over 27 disease states. The company is recognized as a world leader in tests used in the diagnosis of flaviviruses and other arthropod-borne viruses including the first clinical diagnostics for Ross River Fever, Dengue Fever and West Nile Virus. For more information visit www.panbio.com.au.

About Corixa

Corixa is a biopharmaceutical company developing vaccine adjuvants and immunology based products that manage human diseases. Corixa's products are currently in multiple clinical development programs, including several 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, Washington, with additional operations in Hamilton, Montana. For more information, please visit Corixa's Web site at www.corixa.com.

Corixa Forward-Looking Statements

This press release contains forward-looking statements, including statements regarding the potential commercialization of new products containing Corixa intellectual property, and other statements about Corixa's 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 Annual Report on Form 10-K for the year ended December 31, 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.