AVANT Announces Vaccine Adjuvant Licenses with 3M

Business Wire, June 11, 2008

Access to enabling TLR adjuvants to advance novel antibody-based vaccine platform

NEEDHAM, Mass. -- Celldex Therapeutics, Inc. (a wholly-owned subsidiary of AVANT Immunotherapeutics, Nasdaq: AVAN) today announced multi-year clinical research collaborations with the 3M to access their proprietary Immune Response Modifier Resiquimod[TM] (and additional Toll-Like Receptor 7/8 agonists (TLR)) for clinical study with Celldex's proprietary Antigen Presenting Cell (APC) Targeting Technology[TM], for use as vaccine adjuvants.

"The combination of 3M's TLR 7/8 agonists with the APC Targeting Technology(TM) products is synergistic in itself, and we believe that they can also be used to create second generation conjugated vaccines that deliver the vaccine and TLR agonists directly to the immune system within a single construct," said Tibor Keler, Ph.D., Chief Scientific Officer of AVANT Immunotherapeutics. "This collaboration, in addition to our existing agreement with Oncovir, allows us to conduct combination studies with clinically tested TLR agonists. We are now in a position to explore a comprehensive vaccine strategy that targets multiple individual immune activation pathways based on the most recent scientific advances."

The foundation of the APC Targeting Technology(TM) is the ability of the Company's proprietary monoclonal antibodies to deliver vaccines directly to professional APCs, such as dendritic cells and macrophages. Celldex's APC Targeting Technology(TM) product candidates can access the immune system far more efficiently than traditional vaccine approaches, and can be readily combined with adjuvants to enhance immunity against cancer or infectious diseases.

"We believe that our APC Targeting Technology(TM) and our collaborative relationship with 3M and Oncovir provide us with a unique opportunity to develop combination immunotherapies," added Thomas Davis, M.D., AVANT's Chief Medical Officer. "The preclinical data suggest that combinations will be more potent, and the immunotherapy field is eager to see these combination tested. Our ability to license such adjuvants for comprehensive immunotherapy could open a new era."

The 3M and Oncovir products will initially be combined with Celldex's lead APC Targeting Technology(TM) program, CDX-1307, currently in phase I studies for patients with incurable breast, bladder, pancreatic, or colorectal cancer. Additional clinical programs combining APC Targeting Technology(TM) and TLR agonists are planned in oncology and infectious disease indications. Celldex will have the flexibility to use these TLR agonists, alone or in combination, in conjunction with its novel antibody-targeting platform. This will enable the Company to uniquely advance its broad immunotherapy portfolio across a range of disease indications.

About 3M

A recognized leader in research and development, 3M produces thousands of innovative products for dozens of diverse markets. 3M's core strength is applying its more than 40 distinct technology platforms - often in combination - to a wide array of customer needs. With $24 billion in sales, 3M employs 75,000 people worldwide and has operations in more than 60 countries.

About Oncovir

Oncovir, Inc is a pharmaceutical corporation dedicated to the development of nucleic-acid-based clinical therapies for cancer, infectious, immune, and degenerative disorders. Based in Washington, DC, Oncovir has been investigating the use of Hiltonol (Poly ICLC) in a series of clinical studies toward brain cancer and smallpox virus.

About AVANT Immunotherapeutics, Inc.

AVANT Immunotherapeutics and Celldex Therapeutics combined during the first quarter of 2008. AVANT Immunotherapeutics, Inc. is a NASDAQ-listed company discovering and developing innovative vaccines and targeted immunotherapeutics for the treatment of cancer, infectious and inflammatory diseases. AVANT focuses on the use of tumor-specific targets and human monoclonal antibodies (mAbs) to precisely deliver therapeutic agents through its novel "targeted immunization" approach. In addition, AVANT is exploiting its access to proprietary human antibody technology for development of therapeutic monoclonal antibodies (mAbs). AVANT's deep product pipeline consists of products in varying stages of development, with its lead candidate, CDX-110, partnered with Pfizer, Inc., currently undergoing evaluation in a Phase 2b/3 clinical trial in newly diagnosed glioblastoma multiforme, one of the most aggressive forms of brain cancer. AVANT also has five product candidates in its development pipeline including:

* CDX-1307, a product based on its proprietary APC Targeting Technology([TM]), which is in two Phase 1 clinical trials for patients with advanced pancreatic, bladder, breast and colon cancer;

* TP10, a complement inhibitor, in development for transplantation and other indications; 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.