AVANT Immunotherapeutics Announces Hart-Scott Rodino Clearance to License Cancer Vaccine to Pfizer

PHILLIPSBURG, N.J., May 21 /PRNewswire/ -- Celldex Therapeutics (a wholly-owned subsidiary of AVANT Immunotherapeutics, Nasdaq: AVAN) announced today it has received Federal Trade Commission approval under the Hart-Scott Rodino (HSR) Act, clearing AVANT's proposal to award Pfizer exclusive rights to CDX-110, an investigational vaccine currently under development.

On April 16, 2008, Pfizer, Inc. and Celldex announced that they entered into an agreement under which Pfizer would be granted an exclusive worldwide license to CDX-110, currently being evaluated in a Phase 2 study for the treatment of glioblastoma multiforme (GBM). The agreement also gives Pfizer exclusive rights to the use of this vaccine targeting the tumor specific EGFR mutant EGFRvIII in other potential indications.

About CDX-110

CDX-110 is designed to induce or enhance the body's immune responses against EGFRvIII resulting in destruction of tumor cells that express the variant receptor. Single arm Phase 2 clinical trials of CDX-110 in combination with the current standard treatment for patients with GBM have been conducted. Updated clinical data will be released at the American Society for Clinical Oncology Meeting in Chicago on June 2, 2008. A randomized Phase 2 trial is currently enrolling at 24 sites across the United States.

About AVANT Immunotherapeutics, Inc.

AVANT Immunotherapeutics and Celldex Therapeutics combined during the first quarter of 2008. AVANT 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. Identification of the potential of EGFRvIII in cancer diagnosis, prevention and therapy was based on the collaborative efforts of Dr. Bert Vogelstein and Dr. Albert Wong at Johns Hopkins University and Dr. Darell Bigner at Duke University. Application of this discovery toward the development of the CDX-110 vaccine was further advanced by Dr. John Sampson and his colleagues at the Duke University Brain Tumor Center in collaboration with Dr. Amy Heimberger at the MD Anderson Cancer Center. AVANT has several other 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 oral, rapidly-protecting, single-dose and temperature-stable vaccine technology, including combination vaccines for travellers, the military and global health needs.

AVANT has three commercialized products, including Rotarix(R) (partnered with GSK) for the prevention of rotavirus infection and two human food safety vaccines for reducing salmonella infection in chickens and eggs. Additional information on AVANT Immunotherapeutics, Inc. can be obtained through its web site http://www.avantimmune.com/.

AVANT Immunotherapeutics, Inc. Anthony S. Marucci, 781-433-0771 Interim President and CEO BMC Communications Marissa Nelson (212) 477-9007 x21