CELLDEX THERAPEUTICS INITIATES PHASE 2/3 TRIAL OF CDX110.

Celldex Therapeutics, Phillipsburg, N.J, has announced that the company has initiated the ACT III study, a randomized, multi-institution Phase 2/3 clinical trial. The study will investigate the clinical efficacy and safety of Celldex's epidermal growth factor receptor variant III (EGFRvIII) peptide vaccine CDX-110 added to standard-of-care in patients with newly diagnosed glioblastoma multiforme (GBM) that express the variant III mutation of the EGFR receptor.

The CDX-110 investigational immunotherapy activates a patient's immune system against EGFRvIII, a unique protein on cancer cells, recruiting the immune system to attack existing tumor. Prior clinical research led by Dr. John Sampson of Duke University showed promising results of the EGFRvIII vaccine in a Phase 2 study treating brain tumors. The results will be updated by Dr. Sampson at the ASCO Annual Meeting in June.

"We are extremely encouraged by the clinical results we have seen in our CDX-110 patients to date," said Dr. Sampson of Duke. "We are pleased that Celldex is advancing our early work into a Phase 2/3 randomized, multi-center clinical trial to clearly demonstrate this efficacy in a larger treatment group."

The ACT III trial will evaluate CDX-110 in 90 patients, randomized to receive the investigational vaccine treatment or standard therapy in a 2:1 ratio (vaccine to control). Over 20 tertiary brain tumor centers across the United States and Canada will participate in the Phase 2 portion of the study. Specific accruing sites can be identified through the company's web site (www.celldextherapeutics.com) or the NCI clinical trials site (http://clinicaltrials.gov/ct/show/NCT00458601). If improved outcome in disease control is apparent at 6 months, the trial will accrue additional patients to characterize clinical benefit at a Phase 3 level.

About CDX-110

CDX-110 is an investigational immunotherapy that targets the tumor specific molecule EGFRvIII, a functional variant of the epidermal growth factor receptor (EGFR), which is a protein that has been well validated as a target for cancer therapy. This particular variant, EGFRvIII, was discovered in a collaborative effort between Dr. Bert Vogelstein and Dr Albert Wong at Johns Hopkins University and Dr. Darell Bigner at Duke University. Unlike EGFR, EGFRvIII is not present in normal tissues, suggesting this target will enable the development of a tumor-specific therapy for cancer patients. Furthermore, EGFRvIII is a transforming oncogene that can directly contribute to cancer cell growth. While originally discovered in Glioblastoma Multiforme (GBM), the most common and aggressive form of brain cancer, the expression of EGFRvIII has also been observed in various other cancers such as breast, ovarian, metastatic prostate, colorectal, and head & neck cancers. Celldex has exclusive worldwide rights to EGFRvIII vaccines and is pursuing the development of CDX-110 for GBM therapy, as well as in other cancers through additional clinical studies.

About Celldex Therapeutics, Inc.

Celldex Therapeutics, Inc. is a biotechnology company focused on developing therapeutic vaccines that target and stimulate the body's immune system for the treatment of cancer, infectious and autoimmune diseases. Celldex has three product candidates already in or about to enter clinical development targeting multiple cancers and Hepatitis B. Four additional product candidates are in preclinical development for cancer and autoimmune disease. Celldex's proprietary technology platform uses fully human monoclonal antibodies administered directly to patients to target and stimulate dendritic cells -- key cells within the immune system. Celldex was formed in 2004 as a spin-out from Medarex, Inc. The company is headquartered in Phillipsburg, New Jersey.

For more information, call 908/454-7120 or visit http://www.celldextherapeutics.com or http://clinicaltrials.gov/ct/show/NCT00458601