AVANT Immunotherapeutics Announces Name

FOR IMMEDIATE RELEASE/September 29,

AVANT Immunotherapeutics Announces Name

Change to Celldex Therapeutics

- Anthony S. Marucci Appointed President and

- Celldex to Trade Under NASDAQ Symbol CLDX

Effective October 1 -

NEEDHAM, MA September 29,

2008 - AVANT Immunotherapeutics, Inc.

(NASDAQ: AVAN) (the Company ), today announced that, pursuant to a previously

announced shareholder vote, the Company will change its name to Celldex Therapeutics, Inc.

effective October 1, 2008 and shares of the Company s common stock will be

listed on NASDAQ under the ticker symbol CLDX effective at market opening on

the same day. The Board of Directors also announced the appointment of Anthony

S. Marucci, who has been serving as interim President and Chief Executive

Officer since May 2008, as President and Chief Executive Officer of the

Based on a strongly positive vote by the Company s shareholders, we

are assuming the name Celldex Therapeutics, said Anthony S. Marucci, President

and Chief Executive Officer. This change reflects the Company s expertise and

focus on developing therapeutic vaccines and antibodies, including the APC

Targeted Technology platform which is a combination of both and is synonymous

with the Celldex name.

Immunotherapeutics and Celldex Therapeutics completed a merger during the first

quarter of 2008. The combined Company s internal pipeline is fueled by the

creation of novel immunotherapy candidates based on Celldex s Precision

Targeted Immunotherapy Platform (PTIP).

PTIP employs a variety of immunotherapy assets including APC Targeting

Technology , which utilizes human monoclonal antibodies to deliver vaccines

directly to their therapeutic targets.

Since spinning out from Medarex as a private company, Celldex has

built a reputation as a leader in the development of targeted

immunotherapeutics to treat cancer and infectious disease. Mr. Marucci

continued, We are proud to be able to carry on this important work under the

same banner and I am honored to lead the Company forward as President and CEO.

Charles R. Schaller, Chairman of the Board commented, Anthony has

demonstrated strong leadership as Celldex has grown both operationally and

scientifically. We are confident that under his guidance the

Company will continue to make rapid progress in the development of new

immunotherapy-based treatments for cancer and other serious diseases. On behalf

of the Board, I am pleased to announce Anthony s appointment and look forward

to his continued contributions.

In the past six months, Celldex s lead candidate, CDX-110, has been

successfully partnered with Pfizer and has continued to advance in its Phase

2b/3 trial in glioblastoma multiforme. The Company has also further enhanced

the precision targeted immunotherapy platform by completing a licensing

agreement with 3M that provides Celldex with access to TLR agonists for use as

vaccine adjuvants in combination with our proprietary APC therapeutic vaccines.

Celldex Therapeutics, Inc.

Celldex Therapeutics is an integrated biopharmaceutical company that

applies its comprehensive Precision Targeted Immunotherapy Platform to generate

a pipeline of candidates to treat cancer and other difficult-to-treat diseases.

Celldex s immunotherapy platform includes a complementary portfolio of

monoclonal antibodies, antibody-targeted vaccines and immunomodulators to

create novel disease-specific drug candidates. For more information, please

visit http://www.celldextherapeutics.com.

Safe Harbor Statement Under the Private Securities Litigation Reform

release includes forward-looking statements that are subject to a variety of

risks and uncertainties and reflect Celldex s current views with respect to

future events and financial performance.

There are a number of important factors that could cause the actual

results to differ materially from those expressed in any forward-looking

statement made by Celldex. These factors

include, but are not limited to: (1) the successful integration of the

businesses, multiple technologies and programs of Celldex; (2) the ability

to adopt Celldex s APC Targeting TechnologyTM to develop new, safe

and effective vaccines against oncology and infectious disease indications; (3) the

ability to adapt Celldex s vectoring systems to develop new, safe and effective

orally administered vaccines against disease causing agents; (4) the

ability to successfully complete product research and further development,

including animal, preclinical and clinical studies, and commercialization of

CDX-110, CDX-1307, CholeraGarde (Peru-15), Ty800, ETEC E. coli vaccine, and

other products and Celldex s expectations regarding market growth; (5) the

cost, timing, scope and results of ongoing safety and efficacy trials of

CDX-110, CDX-1307, CholeraGarde (Peru-15), Ty800, ETEC E. coli vaccine and

other preclinical and clinical testing; (6) the ability to negotiate

strategic partnerships or other disposition transactions for Celldex s

cardiovascular programs, including TP10 and CETi; (7) the ability of

Celldex to manage multiple clinical trials for a variety of product candidates;

volume and profitability of product sales of Megan Vac 1, Megan Egg

and other future products; (9) GlaxoSmithKline s, or Glaxo s, process of

obtaining regulatory approval for the sale of Rotarix in additional

commercial markets, as well as the timing and success of worldwide

commercialization of Rotarix by Glaxo, which is not within our

control; (10) Glaxo s strategy and business plans to launch and supply

Rotarix worldwide, including in the U.S. and other major markets,

which is not within our control, and its payment of royalties to Celldex; (11) Pfizer s and our strategy and

business plans concerning the continued development and commercialization of

expectations regarding its technological capabilities and

its focus to broader markets for vaccines; (13) changes in existing and

potential relationships with corporate collaborators; (14) the availability,

cost, delivery and quality of clinical and commercial grade materials produced

at Celldex s own manufacturing facility or supplied by contract manufacturers

and partners; (15) the timing, cost and uncertainty of obtaining regulatory

approvals; (16) Celldex s ability to develop and commercialize products before

competitors that are superior to the alternatives developed by such

competitors; (17) Celldex s ability to retain certain members of

management;(18) Celldex s expectations regarding research and development

expenses and general and administrative expenses; (19) Celldex s expectations

regarding cash balances, capital requirements, anticipated royalty payments

(including those from Paul Royalty Fund), revenues and expenses, including