AVANT Signs Cholera Vaccine Agreement With International Vaccine Institute.

Business Editors and Health/Medical Writers

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NEEDHAM, Mass.--(BW HealthWire)--Feb. 21, 2002

AVANT Immunotherapeutics, Inc. (Nasdaq: AVAN) announced today the signing of a clinical research agreement with the International Vaccine Institute ("IVI") aimed at conducting clinical trials of AVANT's Peru-15 cholera vaccine in Bangladesh. IVI, through its Diseases of the Most Impoverished ("DOMI") Program, seeks to accelerate the development and introduction of vaccines against cholera, typhoid fever and shigellosis.

IVI is founded on the belief that the health of children in developing countries can be dramatically improved by the development, introduction and use of new and improved vaccines and these vaccines should be developed through a dynamic interaction among science, public health and business. The DOMI Program has been funded by the Bill and Melinda Gates Foundation.

Under the direction of John D. Clemens, M.D., IVI plans to begin conducting clinical trials of Peru-15 in Bangladesh during 2002. AVANT recently announced results from a Phase IIb human challenge study of Peru-15 that showed 100% protection against moderate and severe diarrhea and 93% protection against any diarrhea. The study results suggest that, if confirmed by further investigation, Peru-15 may be an excellent candidate as a potential single dose, oral vaccine for travelers going to areas where cholera is endemic.

"Cholera is a devastating disease in the developing world," said Una S. Ryan, Ph.D., President and Chief Executive Officer of AVANT Immunotherapeutics, Inc. "We are very pleased to announce this partnership with the IVI and to be donating the vaccine to IVI for clinical studies. The development of a safe and effective cholera vaccine is important for protecting residents, travelers and military personnel from cholera in endemic areas. We see the initiation of this trial as serving the dual role of addressing a significant health issue in the developing world and advancing development of AVANT's travelers' vaccine franchise."

"I am pleased to see clinical development of the Peru-15 vaccine moving forward in Bangladesh," stated John D. Clemens, M.D., Director of the International Vaccine Institute. "Our partnership with AVANT underscores IVI's mission of accelerating vaccine development to relieve the burden of disease in developing countries. IVI works with vaccine partners like AVANT to pursue vaccine development that otherwise may not occur."

AVANT also announced today that it plans to aggressively move its Ty800 typhoid fever vaccine into the clinic and will be conducting two Phase II trials of this oral, single dose vaccine in 2002. Previously, an investigational clinical study of Ty800 was completed at the Massachusetts General Hospital. In addition, the company has entered into a manufacturing agreement with Bio Sidus S.A. of Buenos Aires, Argentina for production of the Ty800 vaccine. Una S. Ryan, Ph.D., President and Chief Executive Officer of AVANT Immunotherapeutics, Inc. said, "Bio Sidus has been our manufacturing partner for production of the Peru-15 vaccine and it only makes sense to expand the relationship to include production of Ty800 as well. We look forward to utilizing their experience and expertise in scaling-up and manufacturing these vaccines in commercial quantities for worldwide sales."

AVANT is developing a series of oral, single dose, genetically attenuated, live bacterial vaccines to prevent travelers' diarrhea and dysentery. Frost & Sullivan, a leading market research firm, estimated in a 1999 report that the worldwide market for travelers' vaccines for diarrheal diseases would reach almost $1 billion in 2005. In addition to the Peru-15 and Ty800 vaccines, a Shigella sonnei vaccine, aimed at the shigella strain most often contracted by travelers, is in preclinical development at AVANT. Also, AVANT plans to expand its Campylobacter vaccine research program to include human applications and to use its E. coli expertise and patented technology to develop a vaccine against ETEC, the most common form of travelers' diarrhea. Many of these vaccines could also meet the healthcare requirements of less developed countries, where the need for cholera vaccines and typhoid fever vaccines is particularly acute.

AVANT Immunotherapeutics, Inc. is engaged in the discovery, development and commercialization of products that harness the human immune system to prevent and treat disease. The company is developing a broad portfolio of vaccines against viral and bacterial diseases, including single-dose oral vaccines aimed at protecting travelers from cholera, typhoid fever and other illnesses. AVANT is also developing compounds with the potential to inhibit harmful complement activation that occurs in response to surgery. In addition, the company is conducting clinical studies of a proprietary vaccine candidate for cholesterol management. AVANT further leverages the value of its technology portfolio through corporate partnerships. Current collaborations encompass the development of an oral human rotavirus vaccine, vaccines to combat threats of biological warfare, and vaccines addressed to human food safety and animal health.

Additional information on AVANT Immunotherapeutics, Inc. can be obtained through our site on the World Wide Web: http://www.avantimmune.com.

Safe Harbor Statement Under the Private Securities Litigation Reform Act of 1995: This release includes forward-looking statements which reflect AVANT's current views with respect to future events and financial performance. The words "believe," "expect," "anticipate," and similar expressions identify forward-looking statements. Investors should not rely on forward-looking statements because they are subject to a variety of risks, uncertainties, and other factors that could cause actual results to differ materially from those expressed in any such forward-looking statements. These factors include, but are not limited to: (1) the ability to successfully complete development and commercialization of the Peru-15, Ty800 and other vaccines and other products, including the cost, timing, scope and results of pre-clinical and clinical testing; (2) the ability to successfully complete product research and further development, including animal, pre-clinical and clinical studies of the Peru-15, Ty800 and other vaccines and other products, and the adaptation of our attenuated vaccine technology to different infectious diseases; (3) the ability of the Company to manage multiple late stage clinical trials for a variety of product candidates; (4) the volume and profitability of product sales of Megan(R) Vac 1 and other future products; (5) changes in existing and potential relationships with corporate collaborators; (6) the cost, delivery and quality of clinical and commercial grade materials supplied by contract manufacturers (7) the timing, cost and uncertainty of obtaining regulatory approvals for the Peru-15, Ty800 and other vaccines and for other products; (8) the ability to obtain substantial additional funding; (9) the ability to develop and commercialize products before competitors; (10) the integration of Megan Health's business and programs; (11) the ability to retain certain members of management; and (12) other factors detailed from time to time in filings with the Securities and Exchange Commission.