June 6, 2003

News Release: AVANT Achieves Milestones in Development of Injectable Anthrax and Oral Anthrax/Plague Vaccines for U.S. Department of Defense

AVANT Immunotherapeutics, Inc. (Nasdaq: AVAN) today announced it has been awarded two additional subcontracts marking further milestones in the company's efforts with DynPort Vaccine Company LLC ('DVC') to develop anthrax and plague vaccines for the U.S. Department of Defense. The first award, in the amount of $344,000, covers stability testing of DVC's injectable anthrax vaccine, which began Phase I clinical testing in October 2002. The second award for approximately $1.3 million, supports pre-clinical animal testing of vaccine constructs being developed by AVANT for an oral combination vaccine against anthrax and plague. DVC is the prime systems contractor for the Defense Department's Joint Vaccine Acquisition Program (JVAP). Headquartered in Frederick, Maryland, JVAP is the lead Defense Department organization for the development and purchase of vaccines for the U.S. military. 'We are very pleased to receive these awards to apply modern biotechnological innovations to the development of vaccines that can offer rapid, effective protection from multiple biological agents,' said Una S. Ryan, Ph.D., President and Chief Executive Officer of AVANT Immunotherapeutics, Inc. 'The second of these contracts, in particular, represents a further milestone towards achieving our goal of $8 million in funding over two years for the oral combination vaccine program, covering vaccine development through preclinical testing. DVC's choice of AVANT to conduct this development program is an important recognition of the strength of our company's vaccine and vector technologies for accomplishing these aims.'

'These subcontracts are very important to AVANT since they provide non-dilutive funding to the company to support a substantial portion of our research and development headcount,'Dr. Ryan concluded.

'AVANT's technology demonstrates promise in the development of both the next-generation of injectable anthrax vaccines and state-of-the-art orally administered vaccines designed to provide protection from multiple agents,'said Terry Irgens, R.Ph., President of DVC. 'We look forward to utilizing AVANT's technology to develop the improved vaccines that will meet the nation's homeland safety and military defense needs.'

In January 2003, AVANT received the first of what is expected to be a series of subcontracts to develop a rapid-acting oral anthrax and plague vaccine based on the company's modified live vaccine technology. This technology uses genetically modified bacteria as vectors, or 'buses,'to deliver plague and anthrax antigens to the immune system in a way that quickly stimulates protective immunity against these microbes - both of which have potential for use as bioweapons. AVANT is conducting the vaccine research at both its Needham, Massachusetts and St. Louis, Missouri laboratories.

About AVANT's Oral Vaccine Technology

AVANT's proposed oral combination vaccine has the potential to offer dramatic advances over current-generation biodefense vaccines. For example, the current generation anthrax vaccine administered to U.S. troops requires individuals to undergo a series of six injections over an 18-month period. The AVANT vaccine confers immunity to anthrax gradually, over a number of weeks. Recipients of the current generation anthrax vaccine have complained of muscular soreness with or at the site of injection. By contrast, the proposed anthrax-plague vaccine to be developed by AVANT is designed to require a single oral dose, confer immunity within days, and cause minimal side effects.

Scientists at AVANT created the vectoring technology as part of the company's development of orally administered bacterial vaccine candidates against cholera (Vibrio cholerae, Peru-15) and typhoid fever (Salmonella typhi, Ty800). Peru-15 and Ty800 were created using genetic techniques to delete genes known to be essential to the virulence of the parent microorganism. As a result of these alterations, AVANT's vaccine candidates have been shown in the clinic to be well tolerated by humans. Moreover, results of a Phase IIb challenge study with AVANT's Peru-15 cholera vaccine candidate demonstrated the ability of a single dose to protect subjects against moderate or severe diarrhea following administration of live Vibrio cholerae bacteria. This study was conducted under the sponsorship of the National Institute of Allergy and Infectious Disease (NIAID) of the National Institutes of Health (NIH) in collaboration with the Walter Reed Army Institute of Research (WRAIR).

About DVC

DynPort Vaccine Company LLC (DVC) is a biopharmaceutical development company dedicated to the development and licensure of safe and efficacious biodefense vaccines for the U.S. Department of Defense (DoD) through the Joint Vaccine Acquisition Program (JVAP). DVC is a joint venture between CSC, one of the world's leading information technology (IT) service companies, and Porton International Inc., a leading vaccine development company focused on the development of biodefense vaccines. Founded in 1997, DVC employs 135 professionals at its headquarters in Frederick, Maryland. For more information about DVC visit http://www.dynport.com.

About AVANT

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 proposed acquisition of UPT and related transactions may not be consummated on the terms currently anticipated or at all; (2) the ability to adapt AVANT's vectoring systems to develop new, safe and effective orally administered vaccines against anthrax and plague or any other microbes used as bioweapons; (3) the ability to successfully complete development and commercialization of CholeraGarde(TM) (Peru-15), Ty800 and of other products; (4) the cost, timing, scope and results of ongoing safety and efficacy trials of 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 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 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 CholeraGarde(TM) (Peru-15) and Ty800, among other purposes, to protect travelers and people in endemic regions from diarrhea causing diseases and for other products; (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.

SOURCE: AVANT Immunotherapeutics, Inc.

AVANT Immunotherapeutics, Inc.Una S. Ryan, Ph.D., President and CEO, 781/433-0771orAvery W. Catlin, Chief Financial Officer, 781/This email address is being protected from spambots. You need JavaScript enabled to view it. Media:Kureczka/Martin AssociatesJoan Kureczka, 415/This email address is being protected from spambots. You need JavaScript enabled to view it.

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