AVANT Receives Licensure of Its Second Food Safety Vaccine for Poultry, MeganEgg.

Health/Medical Writers

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NEEDHAM, Mass.--(BUSINESS WIRE)--Nov. 20, 2003

AVANT Immunotherapeutics, Inc. (Nasdaq: AVAN) today announced that it has received notification from the United States Department of Agriculture (USDA) of the licensure of its Megan(R)Egg vaccine for use in breeding and laying hens.

Megan(R)Egg is a double gene-modified vaccine for use in commercial breeders and egg-layers to protect against infection from Salmonella bacteria that is known to contaminate eggs. Pullets generally receive three vaccinations during the growing period and are protected throughout lay without further vaccination. The primary objective of the vaccine is elimination or reduction of Salmonella enteritidis levels in chickens, principally found in eggs, the birds and their poultry house.

Lohmann Animal Health International (LAHI) will distribute Megan(R)Egg exclusively in North America. LAHI, a private company, is a leader in the North American poultry industry, with an extensive product line of vaccines and related products, a well-established sales and marketing team, and a dedicated customer and technical support group. LAHI is committed to building a powerful force in the avian health industry.

"We and our partner LAHI look forward to continued service to the poultry industry with our new product, Megan(R)Egg for pullet hens, as well as our currently marketed Salmonella vaccine, Megan(R)Vac 1 vaccine for young broilers," said Avery W. Catlin, Chief Financial Officer of AVANT Immunotherapeutics, Inc. "While the reduction of Salmonella sp. in laying and breeder hens and broilers may provide some direct bird health benefit, the primary purpose of the vaccine is increased human food safety."

About Salmonella Risks in Eggs

According to the Center for Disease Control (CDC), egg-associated salmonellosis is an important public health problem in the United States and several European countries. A bacterium, Salmonella enteritidis, can be inside perfectly normal-appearing eggs, and if the eggs are eaten raw or undercooked, the bacterium can cause illness. During the 1980s, illness related to contaminated eggs occurred most frequently in the northeastern United States, but now illness caused by S. enteritidis is increasing in other parts of the country. Approximately 40,000 people develop salmonella infection in the U.S. each year.

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 addressing a wide range of applications including bacterial and viral diseases, chronic human disease, biodefense and food safety. These include single-dose, oral vaccines that protect against important disease-causing agents and a novel, proprietary vaccine candidate for cholesterol management. AVANT's goal is to demonstrate proof-of-concept for its products before leveraging their value through 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. These forward-looking statements are based on management's beliefs and assumptions and information currently available. The words "believe", "expect", "anticipate", "intend", "estimate", "project" and similar expressions which do not relate solely to historical matters identify forward-looking statements. Investors should be cautious in relying 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 integration of multiple technologies and programs; (2) the ability to adapt AVANT's vectoring systems to develop new, safe and effective orally administered vaccines against anthrax and plague or other bioterrorism threats or emerging health care threats; (3) the ability to successfully complete development and commercialization of TP10, CETi-1, CholeraGarde(TM) (Peru-15), Ty800 and other products; (4) the cost, timing, scope and results of ongoing safety and efficacy trials of TP10, CETi-1, CholeraGarde(TM) (Peru-15), Ty800 and other preclinical and clinical testing; (5) the ability to successfully complete product research and further development, including animal, pre-clinical and clinical studies of TP10, CETi-1, CholeraGarde(TM) (Peru-15), Ty800 and other products; (6) the ability of the Company to manage multiple late stage clinical trials for a variety of product candidates; (7) the volume and profitability of product sales of Megan(R)Vac 1 and other future products; (8) changes in existing and potential relationships with corporate collaborators; (9) the availability, cost, delivery and quality of clinical and commercial grade materials supplied by contract manufacturers; (10) the timing, cost and uncertainty of obtaining regulatory approvals to use TP10, CETi-1, CholeraGarde(TM) (Peru-15) and Ty800, among other purposes, for adults undergoing cardiac surgery, to raise serum HDL cholesterol levels and to protect travelers and people in endemic regions from diarrhea causing diseases, respectively; (11) the ability to obtain substantial additional funding; (12) the ability to develop and commercialize products before competitors; (13) the ability to retain certain members of management; and (14) other factors detailed from time to time in filings with the Securities and Exchange Commission. We expressly disclaim any responsibility to update forward-looking statements.