AVANT Immunotherapeutics, Inc. and Celldex Therapeutics Schedule Joint Teleconference for Monday

AVANT Immunotherapeutics, Inc. and Celldex Therapeutics

Schedule Joint Teleconference for Monday, October 22, 2007 at 9:00 AM

MA and Phillipsburg, NJ, October 22, 2007 AVANT

Immunotherapeutics, Inc. (NASDAQ: AVAN) and Celldex Therapeutics, Inc., a

privately-held company, announced today that they will hold a joint

teleconference on Monday, October 22 at 9:00 AM EDT to discuss the proposed

merger agreement announced earlier this morning in a joint press release.

call may be accessed by visiting www.avantimmune.com or

www.celldextherapeutics.com. The webcast and telephonic replay will be

available following the filing of the conference call transcript with the SEC.

also access the call with the following dial-in information:

access the replay with the following dial-in information:

Immunotherapeutics, Inc.:

AVANT Immunotherapeutics, Inc. is a Massachusetts-based NASDAQ-listed

company discovering and developing innovative vaccines and therapeutics that

harness the human immune system to prevent and treat disease. AVANT s

innovative bacterial vector delivery technologies with unique manufacturing and

preservation processes offer the potential for a new generation of vaccines.

AVANT has three commercialized products, including Rotarix for the

treatment of rotavirus and two human food safety vaccines for reducing

salmonella infection in chickens and eggs. AVANT also has four product

candidates in its development pipeline, an anti-inflammatory agent, TP10, and

three candidates based on its oral, rapidly-protecting, single-dose and

temperature-stable vaccine technology, including combination vaccines for travelers,

the military and global health needs.

Celldex Therapeutics, Inc.:

Celldex Therapeutics, Inc. is an innovative, privately-held New

Jersey-based biopharmaceutical company spun-out of Medarex, Inc. (NASDAQ:

MEDX) developing targeted immunotherapeutics for the treatment of cancer,

infectious and inflammatory diseases. Celldex focuses on the use of

tumor-specific targets and human monoclonal antibodies (mAbs) to precisely

deliver therapeutic agents through its novel targeted immunization approach.

Celldex s deep product pipeline consists of products in varying stages of

development, with its lead candidate currently undergoing evaluation in a Phase

2/3 clinical trial in newly diagnosed glioblastoma multiforme, one of the most

aggressive forms of brain cancer. Celldex is also running clinical trials for

several products based on its proprietary APC Targeting Technology ,

which delivers fully human monoclonal antibodies directly to patients to target

and stimulate dendritic cells and macrophages key cells within the immune

Information about the Merger and Where to Find It

communication contains forward-looking statements within the meaning of the

Private Securities Litigation Reform Act of 1995. These statements are

typically preceded by words such as believes, expects, anticipates, intends,

will, may, should, or similar expressions. These forward-looking

statements are subject to risks and uncertainties that may cause actual future

experience and results to differ materially from those discussed in these

forward-looking statements. Important factors that might cause such a difference

include, but are not limited to, costs related to the Merger, failure of AVANT s

stockholders to approve the Merger; AVANT s or Celldex s inability to satisfy

the conditions of the Merger; AVANT s inability to maintain its NASDAQ listing;

the risk that AVANT s and Celldex s businesses will not be integrated

successfully; the combined company s inability to further identify, develop and

achieve commercial success for new products and technologies; the possibility

of delays in the research and development necessary to select drug development

candidates and delays in clinical trials; the risk that clinical trials may not

result in marketable products; the risk that the combined company may be unable

to successfully secure regulatory approval of and market its drug candidates;

the risks associated with reliance on

financing to meet capital requirements; risks associated with Celldex s new and

uncertain technology; risks of the development of competing technologies; risks

related to the combined company s ability to protect its proprietary

technologies; risks related to patent-infringement claims; risks of new,

changing and competitive technologies and regulations in the U.S. and

internationally; and other events and factors disclosed previously and from

time to time in AVANT s filings with the Securities and Exchange Commission,

including AVANT s Annual Report on Form 10-K for the year ended December 31,

2006. The companies do not undertake any obligation to release publicly any

revisions to such forward-looking statements to reflect events or circumstances

after the date hereof or to reflect the occurrence of unanticipated events.

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 joint registration statement/proxy statement 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.

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.

Contact information: