AVANT Receives Additional Defense Contract for Clinical Testing of Plague Component for Oral Anthrax/Plague Vaccine.

Business Editors/Health/Medical Writers

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NEEDHAM, Mass.--(BUSINESS WIRE)--April 21, 2004

AVANT Immunotherapeutics, Inc. (Nasdaq: AVAN) today announced it has been awarded an additional subcontract marking further milestones in the company's efforts with DynPort Vaccine Company LLC ("DVC") to develop biodefense vaccines for the U.S. Department of Defense. The award for $3 million supports the human clinical testing of a plague vaccine candidate being developed by AVANT for use in 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 this award which demonstrates our continuing competitiveness in the development of next generation biodefense vaccines," said Una S. Ryan, Ph.D., President and Chief Executive Officer of AVANT Immunotherapeutics, Inc. "We have made great strides in this program over the past 15 months and are now prepared to test the plague vaccine candidate in humans for safety and immunogenicity. To date we have received subcontracts totaling over $7 million in funding for this oral combination vaccine program. These subcontracts provide non-dilutive funding to the company to support a substantial portion of the development of our vectored vaccine technologies, which offers opportunities for developing a wide range of vaccines against bacterial, and potentially viral diseases."

"AVANT's technology demonstrates promise in the development of 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 and June 2003, AVANT received the first two awards 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 DVC

DynPort Vaccine Company LLC (DVC) is a biopharmaceutical company dedicated to the development and licensure of safe and efficacious biodefense vaccines. Biodefense biologics in development include vaccinia immune globulin, smallpox vaccine, next-generation anthrax vaccine, plague vaccine, Venezuelan equine encephalitis vaccine, tularemia vaccine, botulinum bivalent and multivalent vaccines and botulinum polyclonal antitoxin. Founded in 1997, DVC employs nearly 120 professionals at its headquarters in Frederick, Maryland. For more information about DVC visit http://www.dynport.com.

About AVANT

AVANT Immunotherapeutics, Inc. discovers, develops and sells innovative vaccines and therapeutics that harness the human immune system to prevent and treat disease. The company has developed a broad, well-staged pipeline of vaccines and therapeutics for large, high-value, under-served markets. Six of AVANT's products are in clinical development. These include an oral human rotavirus vaccine, a treatment to reduce complement-mediated tissue damage associated with cardiac by-pass surgery, and a novel vaccine for cholesterol management. AVANT has also assembled a technology platform that enables the creation of rapid-protecting, single-dose, oral vaccines that remain stable without refrigeration. The company is developing applications of this vaccine technology in four areas: biodefense, travelers' vaccines, global health needs, and human food safety. AVANT's goal is to demonstrate proof-of-concept for its products before leveraging further development through both traditional pharmaceutical partnerships and collaborations with governmental and other organizations.

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, Megan(R)Egg 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.