AVANT Appeals Delisting Notification From NASDAQ

Business Wire, Jan 9, 2008

NEEDHAM, Mass. -- AVANT Immunotherapeutics, Inc. (Nasdaq: AVAN) announced today that on January 8, 2008 it received a letter from The NASDAQ Stock Market indicating that AVANT had failed to regain compliance with the Nasdaq Capital Market's minimum bid price requirement of $1.00 per share for continued listing of AVANT's common stock on the Nasdaq Capital Market as set forth in Marketplace Rule 4310(c)(4) (the "Staff Determination"). As a result, AVANT's common stock is subject to be delisted from the Nasdaq Capital Market on January 17, 2008. Following procedures set forth in the Nasdaq Marketplace Rule 4800 series, AVANT has requested a hearing before a Nasdaq Listing Qualifications Panel (the "Panel") to review the Staff Determination. The hearing request will stay the delisting of AVANT's common stock, pending the decision of the Panel, allowing it to continue to trade on the Nasdaq Capital Market. Historically Panels have generally viewed a near-term reverse stock split as the only definitive plan acceptable to resolve a bid price deficiency. AVANT expects to execute such a reverse stock split in connection with its pending merger with Celldex Therapeutics, Inc. ("Celldex"). There can be no assurance however, that the Panel will grant AVANT's request for continued listing on the Nasdaq Capital Market.

In the event that the Panel denies AVANT's request for continued listing on the Nasdaq Capital Market, AVANT's common stock shall be delisted from the Nasdaq Capital Market. Following such delisting, AVANT's common stock could be eligible to trade on the OTC Bulletin Board. Further, AVANT may apply to trade on the Nasdaq Global Market following the closing of the proposed merger with Celldex. Additional information on AVANT Immunotherapeutics, Inc. can be obtained through our site on the World Wide Web: http://www.avantimmune.com.

Additional Information about the Merger and Where to Find It

This communication may be deemed to be solicitation material in respect of the proposed merger of AVANT and Celldex. In connection with the proposed merger, AVANT and Celldex intend to file relevant materials with the SEC, including AVANT's proxy statement/prospectus on Form S-4.

SHAREHOLDERS OF AVANT ARE URGED TO READ ALL RELEVANT DOCUMENTS FILED WITH THE SEC, INCLUDING AVANT'S PROXY STATEMENT, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION.

Investors and security holders will be able to obtain the documents free of charge at the SEC's web site, http://www.sec.gov, and AVANT shareholders will receive information at an appropriate time on how to obtain transaction-related documents for free from AVANT. Such documents are not currently available.

Participants in the Solicitation

The directors and executive officers of AVANT and Celldex may be deemed to be participants in the solicitation of proxies from the holders of AVANT common stock in respect of the proposed transaction. Information about the directors and executive officers of AVANT is set forth in the proxy statement for AVANT's most recent 10-K, which was filed with the SEC on March 16, 2007. Investors may obtain additional information regarding the interest of AVANT and its directors and executive officers, and Celldex and its directors and executive officers in the proposed transaction by reading the proxy statement regarding the acquisition when it becomes available.

Safe Harbor Statement Under the Private Securities Litigation Reform Act of 1995: The statements made in this press release which are not statements of historical fact are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, including, without limitation, statements that may be identified by words such as "expectations," "remains," "focus," "expected," "prospective," "expanding," "building," "continue," "progress," "plan," "efforts," "hope," "believe," "objectives," "opportunities," "will," "seek," and other expressions which are predictions of or indicate future events and trends and which do not constitute historical matters identify forward-looking statements. These statements also include statements regarding: (i) AVANT's expectations regarding its restructuring and quarterly cash burn rate, (ii) AVANT's expectations regarding the Merger (iii) AVANT's expectations of royalty payments from PRF related to Rotarix, (iv) AVANT's expectations to initiate its own sponsored double-blind, placebo-controlled Phase 2 dose-ranging trial of Ty800 and Phase 1/2 trial of its ETEC Cholera vaccine candidate, and (v) statements made regarding AVANT's goals for its programs and products. This release includes forward-looking statements that are subject to a variety of risks and uncertainties and reflect AVANT's current views with respect to future events and financial performance. There are a number of important factors that could cause the actual future experience and results to differ materially from those expressed in any forward-looking statement made by AVANT.