AVANT Announces Preliminary Results of its Phase II Study of TP10 in Adults Undergoing Cardiac Surgery.

Business Editors and Health/Medical Writers

NEEDHAM, Mass.--(BW HealthWire)--Feb. 20, 2002

AVANT Immunotherapeutics, Inc. (Nasdaq: AVAN) today announced that TP10, its lead complement inhibitor, failed to meet the primary endpoint in a double-blind, placebo-controlled Phase II study in adult patients undergoing high risk cardiac surgery.

Announcing the results, Dr. Alistair Wheeler MD, Vice President, Medical Affairs of AVANT said, "there were no clinically important differences between placebo and any of the four dose groups in the study. A total of 564 patients were randomized into the study to receive either one of four doses (1, 3, 5 or 10 mg/kg) of TP10, or placebo, as a thirty-minute intravenous infusion and were followed for 28 days post surgery. The primary efficacy endpoint of the study was the comparison of TP10 treated patients versus placebo who experienced either death, myocardial infarction, required prolonged intubation or prolonged intra-arterial balloon pump therapy. TP10 was well tolerated with no apparent differences in the safety profiles of the treatment groups."

"Obviously, we are extremely disappointed by the results of this study," said Una S. Ryan, Ph.D., President and Chief Executive Officer of AVANT Immunotherapeutics, Inc. "We are evaluating the future of the TP10 program but we no longer plan to advance TP10 in clinical development on our own nor do we intend to put anymore AVANT resources into this program. We will try to capture what value we can for the TP10 program," continued Dr. Ryan.

Dr. Ryan further stated, "We continue to focus AVANT's resources on our vaccines programs. In particular, we are pleased to be advancing the two lead products in our travelers' vaccines portfolio, CholeraGarde(TM) cholera vaccine and Ty800 typhoid vaccine, in the clinic. We are excited about developing a business franchise for safe, effective oral travelers' vaccines that can be administered with a single dose. In addition, we continue to advance CETi-1, our novel immunotherapeutic for cholesterol management, through clinical development. Finally with our partner, GlaxoSmithKline, we are developing a two-dose oral rotavirus vaccine which is expected to enter late-stage clinical studies this year."

Dr. Ryan, Dr. Wheeler and Mr. Catlin will host a conference call at 2:00 PM EST on Wednesday, February 20, 2002 to discuss the results of the TP10 adult Phase II study. To access the conference call, dial 800-360-9865 (within the United States), or 973-694-6836 (if calling from outside the U.S.). An audio replay will be available immediately following the call for approximately one week and can be accessed by dialing 800-428-6051 (within the U.S.), or 973-709-2089 (if calling from outside the U.S.). The passcode for the audio replay is 232690.

The call will also be broadcast via the Company's website: www.avantimmune.com. In order to access the webcast, your PC must have a sound card, speakers and Windows Media Player software. It is recommended that you configure your PC in advance of the webcast as the software download and installation can take several minutes.

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 against viral and bacterial diseases, including single-dose oral vaccines aimed at protecting travelers from cholera, typhoid fever and other illnesses. In addition, the company is conducting clinical studies of a proprietary vaccine candidate for cholesterol management. AVANT further leverages the value of its technology portfolio through corporate 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 within the meaning of the securities laws which reflect AVANT's current views with respect to future events and financial performance. The words "believe," "expect," "anticipate," and similar expressions identify forward-looking statements. Investors should not rely 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 ability to successfully complete development and commercialization of TP10 for use in infants and adults undergoing cardiac surgery and other purposes and of other products, (2) the cost, scope and results of ongoing safety and efficacy trials of TP10 and other preclinical and clinical testing; (3) the ability to successfully complete product research and further development, including animal, pre-clinical and clinical studies of TP10 and other products, and the adaptation of our attenuated vaccine technology to different infectious diseases; (4) the ability of the Company to manage multiple late stage clinical trials for a variety of product candidates; (5) the volume and profitability of product sales of Megan(R)Vac 1 and other future products; (6) changes in existing and potential relationships with corporate collaborators; (7) the cost, delivery and quality of clinical and commercial grade materials supplied by contract manufacturers; (8) the time, cost and uncertainty of obtaining regulatory approvals to use TP10, among other purposes, for infants and adults undergoing cardiac surgery and for other products; (9) the ability to obtain substantial additional funding; (10) the ability to develop and commercialize products before competitors; (11) the ability to retain certain members of management; and (12) other factors detailed from time to time in filings with the Securities and Exchange Commission.