Avant Immunotherapeutics Receives Key Patent for Its Cholesterol Management Vaccine, CETi-1.

Business Editors and Health/Medical Writers

BIOWIRE2K

AVANT Immunotherapeutics, Inc. (Nasdaq: AVAN) announced today that the United States Patent and Trademark Office has issued U.S. patent 6,410,022 to the company covering AVANT's novel vaccine for cholesterol management, CETi-1. The CETi-1 vaccine induces antibodies against a portion of the cholesteryl ester transfer protein (CETP), a serum protein responsible for cholesterol transfer from high-density lipoprotein (HDL) cholesterol to low-density lipoprotein cholesterol (LDL). In doing so, the vaccine blocks the ability of CETP to shuttle cholesterol from HDL to LDL, thus potentially causing blood serum levels of the heart-protective HDL cholesterol to rise.

This newly issued U.S. patent is the key patent that underlies the CETi-1 product candidate presently under study in a Phase II clinical trial, and it underpins AVANT's broad intellectual property coverage of vaccine approaches to inhibiting CETP. AVANT's expanded CETP vaccine patent portfolio now also includes foreign patents, patents on alternative vaccine compositions including nucleic acid- and protein-based vaccines, and additional patent applications acquired from The Immune Response Corporation (Nasdaq: IMNR).

"Atherosclerosis is the biggest killer in the western world," said Una S. Ryan, Ph.D., President and Chief Executive Officer of AVANT, "In the $18 billion global cholesterol drug market, low HDL cholesterol is an important risk factor for atherosclerosis and represents a vast unmet medical need. This patent strengthens our extensive intellectual property and leadership position in atherosclerosis vaccines."

The principle of the CETi-1 approach is to harness an individual's own immune system by periodic vaccinations to control the activity of an important cholesterol transport mechanism and to thereby improve HDL levels. Elevated HDL or `good' cholesterol acts to protect against atherosclerosis, while elevated LDL (low-density lipoprotein) or `bad' cholesterol acts to promote atherosclerosis. Atherosclerosis is an underlying cause of heart attacks, strokes, and peripheral vascular disease, and the cause of over 50% of the deaths in the western world.

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 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 CETi-1 and of other products; (2) the cost, timing, scope and results of ongoing safety and efficacy trials of CETi-1 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 CETi-1 and other products; (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 timing, cost and uncertainty of obtaining regulatory approvals to use CETi-1, among other purposes, to raise serum HDL cholesterol levels and for other products; (9) the ability to obtain substantial additional funding; (10) the ability to develop and commercialize products before competitors; (11) the integration of Megan Health's business and programs; (12) the ability to retain certain members of management; and (13) other factors detailed from time to time in filings with the Securities and Exchange Commission.