AVANT Immunotherapeutics Says Promise of Rotarix(R) Rotavirus Vaccine for Reducing Deaths, Hospitalizations Due to Rotavirus Disease Highlighted in New England Journal of Medicine

Partner GSK's Global Commercialization of Rotarix Continues

AVANT Immunotherapeutics (Nasdaq: AVAN) today announced that datafrom a Phase 3 study of Rotarix(R), the company's two-dose oralrotavirus vaccine being developed and commercialized globally byGlaxoSmithKline, were published today in the January 5 issue of theNew England Journal of Medicine. Accompanying the publication of theclinical article, which demonstrated the safety and efficacy of thevaccine in a randomized, double-blind, Phase 3 trial, was an editorialcommenting on the positive study results and the promise of Rotarix(R)and a second new rotavirus vaccine in development by others. Theeditorial noted the value of a safe and effective rotavirus vaccineboth to save lives in developing nations, where rotavirus disease is amajor cause of infant death, and to reduce the economic burden of thedisease in industrialized countries by reducing hospitalizations andlost workdays.

"These publications clearly recognize the need for a safe andeffective rotavirus vaccine like Rotarix(R)," said Una S. Ryan,President and Chief Executive Officer of AVANT Immunotherapeutics."Our partner GlaxoSmithKline has undertaken a worldwide developmenteffort that has now led to approvals for Rotarix in 25 countries and arecommendation from the European regulatory authorities for approvalin Europe. Most recently it has been reported that GlaxoSmithKline ismaking 8 million doses for universal coverage in Brazil."

ABOUT ROTARIX(R)

Rotarix(R) has been developed by GSK Biologicals since 1997 whenit was in-licensed from AVANT Immunotherapeutics. Dr Richard Wardoriginally developed the vaccine at the Cincinnati Children's HospitalMedical Center.

Rotarix(R) is the first human rotavirus vaccine derived from ahuman virus strain available in the market. The vaccine, which isgiven orally, confers significant protection against rotavirusdiarrhea. Clinical trials have shown high efficacy against the mostprevalent rotavirus strains. The vaccine can be co-administered withall major infant vaccines including oral polio vaccine. It is given ina two-dose schedule as of six weeks of age, allowing for an earlyprotection.

Since Rotarix(R) launch in Mexico in 2004, an additional 24licenses have been granted worldwide (12 Latin American countriesincluding Brazil; Philippines and Singapore being the first Asiancountries). Furthermore, Rotarix(R) has been filed in 75 countries.There are plans to file in the US where discussions are ongoing withthe FDA.

Recently, Brazil and Panama included for the first time therotavirus vaccine in their national official vaccination calendars. Aspart of the government's pediatric immunization program, vaccinationwith Rotarix(R) will be available free at public health clinics inBrazil and Panama.

About GlaxoSmithKline Biologicals

GSK Biologicals, one of the world's leading vaccine manufacturers,is located in Rixensart, Belgium, which is the centre of allGlaxoSmithKline's activities in the field of vaccine research,development and production. GSK Biologicals employs more than 1,000research scientists, who are devoted to discovering new vaccines anddeveloping more cost-effective and convenient combination products toprevent infections that cause serious medical problems worldwide. GSKBiologicals future vaccine pipeline contains more than 20 new vaccinesin clinical development.

In 2004, GSK Biologicals distributed more than 1.5 billion dosesof vaccines to 168 countries in both the developed and the developingworld - an average of 45 doses per second. Of those vaccine doses,approximately 140 million were doses of combination paediatricvaccines, which protect the world's children against a minimum ofthree - and as many as six - diseases in one vaccine. For moreinformation, visit GlaxoSmithKline's vaccine websites atwww.gsk-bio.com.

About AVANT Immunotherapeutics, Inc.

AVANT Immunotherapeutics, Inc. discovers and develops innovativevaccines and therapeutics that harness the human immune system toprevent and treat disease. Six of AVANT's products are in clinicaldevelopment, including a treatment to reduce complement-mediatedtissue damage associated with cardiac bypass surgery and a novelvaccine for cholesterol management. AVANT is also developing apipeline of bacteria-fighting products for biodefense, travelers'vaccines, and global health needs based on AVANT'S rapid-protecting,single-dose, oral and temperature stable vaccine technology.Additional information on AVANT Immunotherapeutics, Inc. can beobtained through our site on the World Wide Web:http://www.avantimmune.com.

Safe Harbor Statement Under the Private Securities LitigationReform Act of 1995: This release includes forward-looking statementswhich reflect AVANT's current views with respect to future events andfinancial performance. These forward-looking statements are based onmanagement's beliefs and assumptions and information currentlyavailable. The words "believe", "expect", "anticipate", "intend","estimate", "project" and similar expressions which do not relatesolely to historical matters identify forward-looking statements.Investors should be cautious in relying on forward-looking statementsbecause they are subject to a variety of risks, uncertainties, andother factors that could cause actual results to differ materiallyfrom those expressed in any such forward-looking statements. Thesefactors include, but are not limited to: (1) the integration ofmultiple technologies and programs; (2) the ability to adapt AVANT'svectoring systems to develop new, safe and effective orallyadministered vaccines against anthrax and plague or other bioterrorismthreats or emerging health care threats; (3) the ability tosuccessfully complete development and commercialization of TP10,CETi-1, CholeraGarde(R) (Peru-15), Ty800 and other products; (4) thecost, timing, scope and results of ongoing safety and efficacy trialsof TP10, CETi-1, CholeraGarde(R) (Peru-15), Ty800 and otherpreclinical and clinical testing; (5) the ability to successfullycomplete product research and further development, including animal,pre-clinical and clinical studies of TP10, CETi-1, CholeraGarde(R)(Peru-15), Ty800 and other products; (6) the ability of the Company tomanage multiple late stage clinical trials for a variety of productcandidates; (7) the volume and profitability of product sales ofMegan(R)Vac 1, Megan(R)Egg and other future products; (8) the processof obtaining regulatory approval for the sale of Rotarix (R) in majorcommercial markets, as well as the timing and success of worldwidecommercialization of Rotarix (R) by our partner, GlaxoSmithKline; (9)changes in existing and potential relationships with corporatecollaborators; (10) the availability, cost, delivery and quality ofclinical and commercial grade materials supplied by contractmanufacturers; (11) the timing, cost and uncertainty of obtainingregulatory approvals to use TP10, CETi-1, CholeraGarde(R) (Peru-15)and Ty800, among other purposes, for adults undergoing cardiacsurgery, to raise serum HDL cholesterol levels and to protecttravelers and people in endemic regions from diarrhea causingdiseases, respectively; (12) the ability to obtain substantialadditional funding; (13) the ability to develop and commercializeproducts before competitors; (14) the ability to retain certainmembers of management; and (15) other factors detailed from time totime in filings with the Securities and Exchange Commission. Weexpressly disclaim any responsibility to update forward-lookingstatements.