Biopharmaceuticals Regulatory

 News Release - February 27, 2006

AVANT Announces that the European Regulatory Authorities Have Approved Rotarix(R) Rotavirus Vaccine

Partner GlaxoSmithKline to Make Milestone Payment to AVANT

NEEDHAM, Mass.--(HSMN NewsFeed)--Feb. 27, 2006--AVANT Immunotherapeutics (Nasdaq: AVAN ) today announced that its partner, GlaxoSmithKline (GSK) Biologicals, has received approval from the European Commission for ROTARIX® in the European Union (EU). ROTARIX® will be the first rotavirus vaccine available to children in Europe for the prevention of gastroenteritis caused by rotavirus. GSK intends to introduce this vaccine throughout Europe now that marketing authorization has been granted.

"We are delighted that our partner GSK has received approval of ROTARIX® in Europe," said Una S. Ryan, Ph.D., President and Chief Executive Officer of AVANT Immunotherapeutics. "European approval marks a significant milestone for the global commercialization of ROTARIX®, which has already been approved for commercial use in an additional 33 countries. It brings in a milestone payment from GSK and leads to a substantial payment of $40 million to AVANT through its transaction with Paul Royalty Fund ("PRF")." In May 2005, AVANT entered into an agreement whereby an affiliate of PRF purchased an interest in the net royalties AVANT will receive on worldwide sales of ROTARIX®. The terms of the agreement with PRF include an upfront unconditional payment of $10 million previously received by AVANT and the following milestone payments: (i) $40 million on product launch in the European Union, and (ii) between $9 million and $11 million on product launch in the United States, depending on date of the launch. Under the PRF agreement, AVANT retains 50% of the GSK $4 million milestone payment triggered by the European approval, with the balance payable to PRF and Cincinnati Children's Hospital Medical Center ("CCH").

Virtually every child worldwide will experience an episode of rotavirus disease by the time they reach 5 years of age, irrespective of where they live or how rich or poor they are1. Globally, rotavirus infections are responsible for over 600,000 deaths per year globally - one child every minute1,2. Rotavirus disease causes hospitalization of 87,000 babies and over 700,000 visits to the doctor each year in Europe3. In total an estimated 3.6 million of the 23.6 million children under 5 years of age suffer from rotavirus gastroenteritis (RVGE) in the EU each year4.

According to GSK, the rotavirus market potential by 2010 is estimated between U.S. $1.75 - $2.3 billion. Europe accounts for an estimated 20% of the total market.

About ROTARIX®

ROTARIX® is an oral, two-dose, live attenuated vaccine against rotavirus disease in infants that was licensed in 1997 by AVANT Immunotherapeutics to GSK for worldwide commercialization. Dr. Richard Ward originally developed the vaccine at Cincinnati Children's Hospital Medical Center.

ROTARIX® is the first human rotavirus vaccine derived from a human virus strain available in the market. The vaccine, which is given orally, confers significant protection against rotavirus diarrhea. Clinical trials have shown high efficacy against the most prevalent rotavirus strains. The vaccine can be co-administered with all major infant vaccines including oral polio vaccine5. It is given in a two-dose schedule as of six weeks of age, allowing for early protection.

In addition to the European license, an additional 33 licenses have been granted worldwide (16 Latin American countries including Brazil; Philippines and Singapore being the first Asian countries). Furthermore, ROTARIX® has been filed in over 75 countries. ROTARIX® is not approved in the US, however GSK is in late stage development discussions with the FDA regarding licensure of ROTARIX® in the US market.

Recently, Brazil, Panama and Venezuela included for the first time the rotavirus vaccine in their national official vaccination calendars. As part of the government's pediatric immunization program, vaccination with ROTARIX® will be available free at public health clinics in those countries.

About GlaxoSmithKline Biologicals

GSK Biologicals, one of the world's leading vaccine manufacturers, is located in Rixensart, Belgium, which is the centre of all GlaxoSmithKline's activities in the field of vaccine research, development and production. GSK Bio employs more than 1,500 research scientists, who are devoted to discovering new vaccines and developing more cost-effective and convenient combination products to prevent infections that cause serious medical problems worldwide.

In 2005, GSK Bio distributed more than 1.2 billion doses of vaccines to 165 countries in both the developed and the developing world - an average of more than 3 million doses per year. In the next five years, GSK expects to launch more major new vaccines: an HPV vaccine targeting cervical cancer, a vaccine to prevent pneumococcal disease, an improved flu vaccine for the elderly, and a meningitis combination vaccine for infants in the US.

GlaxoSmithKline -- one of the world's leading research-based pharmaceutical and healthcare companies -- is committed to improving the quality of human life by enabling people to do more, feel better and live longer. For more information, visit GlaxoSmithKline's vaccine websites at www.gsk-bio.com.

About AVANT Immunotherapeutics, Inc.

AVANT Immunotherapeutics, Inc. discovers and develops innovative vaccines and therapeutics that harness the human immune system to prevent and treat disease. Six of AVANT's products are in clinical development, including a treatment to reduce complement-mediated tissue damage associated with cardiac bypass surgery and a novel vaccine for cholesterol management. AVANT is also developing a pipeline 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 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® (Peru-15), Ty800 and other products; (4) the cost, timing, scope and results of ongoing safety and efficacy trials of TP10, CETi-1, CholeraGarde® (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® (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®Vac 1, Megan®Egg and other future products; (8) the process of obtaining regulatory approval for the sale of ROTARIX ® in major commercial markets, as well as the timing and success of worldwide commercialization of ROTARIX ® by our partner, GlaxoSmithKline; (9) changes in existing and potential relationships with corporate collaborators; (10) the availability, cost, delivery and quality of clinical and commercial grade materials supplied by contract manufacturers; (11) the timing, cost and uncertainty of obtaining regulatory approvals to use TP10, CETi-1, CholeraGarde® (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; (12) the ability to obtain substantial additional funding; (13) the ability to develop and commercialize products before competitors; (14) the ability to retain certain members of management; and (15) 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.

References

1. Parashar UD et al. Global illness and deaths caused by rotavirus disease in children. Emerg Infect Dis 2003;9(5):565-72

2. Parashar UD. Rotavirus and Rotavirus Vaccines Proc 6th Int Rotavirus Symp, July 7-9, 2004, Mexico City

3. Soriano-Gabarro M, et al. Burden of rotavirus disease in European countries. Paed Infect Dis J 2006:25 (1):S7-S11

4. Ruiz-Palacios GM, et al. A trial to assess the efficacy and safety of an attenuated vaccine against severe rotavirus gastroenteritis. N Engl J Med 2006;354 : (1) : 11-22

5. Steele AD. et al. Concomitant administration of live attenuated oral rotavirus vaccine (RIX4414) with poliovirus vaccines in African infants. Poster presented at ESPID annual meting, May 2005.

Source: AVANT Immunotherapeutics

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