– CDX-011 granted Fast Track designation by the FDA

NEEDHAM, MA, USA | September 20, 2010 | Celldex Therapeutics, Inc. (NASDAQ: CLDX – News) today announced that the first patient has been treated in a randomized Phase 2b study of the Company’s CDX-011 (glembatumumab vedotin) antibody drug conjugate in glycoprotein NMB (GPNMB) expressing advanced, refractory breast cancer patients. CDX-011 targets the protein GPNMB, which is over expressed in a variety of cancers including breast cancer, melanoma, and brain tumors.

“The CDX-011 antibody drug conjugate provides a targeted intervention for GPNMB expressing breast cancer, including patients with triple-negative disease” said Tom Davis, MD, Chief Medical Officer of Celldex Therapeutics, Inc. “This Phase 2b trial will target patients whose tumors express GPNMB and is anticipated to include a significant proportion of patients with difficult-to-treat triple-negative tumors. It will build upon the positive Phase 1/2 trial which demonstrated encouraging activity in both of these patient subsets.”

The study is a randomized, multi-center, controlled trial that will enroll 120 patients with heavily pre-treated, advanced breast cancer who are unlikely to benefit from any approved therapies and whose tumors are confirmed to express GPNMB via a validated, centralized diagnostic assay. It is anticipated that a significant portion of the enrolled patients will have triple-negative disease, since GPNMB is frequently expressed in this patient population. Patients will be randomized (2:1) to receive either CDX-011 or single-agent “Investigator’s Choice” chemotherapy. Activity endpoints will include response rate, progression-free survival (PFS) and overall survival (OS). The study will be conducted in approximately 25 academic and community sites across the U.S. Preliminary results are expected in Q4 2011.

In May, the U.S Food and Drug Administration (FDA) granted Fast Track designation to CDX-011 for the treatment of advanced, refractory or resistant GPNMB-expressing breast cancer.

About Breast Cancer

Breast cancer is the most common cancer in women and a leading cause of death in the United States. According to the American Cancer Society, more than 180,000 women will be diagnosed with invasive breast cancer in 2009 with more than 40,000 deaths attributed to this disease. Despite recent advances in therapy, the median survival of patients with metastatic breast cancer is 2 to 3 years, while patients with "triple-negative" or "basal-like" breast cancer have limited treatment options due to lack of over-expression of HER2, estrogen and progesterone receptors and poorer outcomes. Therefore, a significant unmet need remains for novel therapeutic approaches for patients with locally advanced and metastatic breast cancer who have failed other therapies.

About CDX-011

CDX-011 (glembatumumab vedotin) is an antibody-drug conjugate (ADC) that consists of a fully-human monoclonal antibody, CR011, linked to a potent cell-killing drug, monomethyl-auristatin E (MMAE). The ADC technology, comprised of MMAE and a stable linker system for attaching it to CR011, was licensed from Seattle Genetics, Inc. The ADC is designed to be stable in the bloodstream. Following intravenous administration, CDX-011 targets and binds to GPNMB, a specific protein that is expressed in at least 40% of breast cancers as well as other tumor types, and which promotes the migration, invasion, and metastasis of breast cancer. Upon internalization into the targeted cell, CDX-011 is designed to release MMAE from CR011 to produce a cell-killing effect. CDX-011 has been shown to be safe and active, with observed objective responses, in two positive Phase 1/2 trials in metastatic breast cancer and advanced melanoma. In May 2010, the U.S Food and Drug Administration (FDA) granted Fast Track designation to Celldex’s CDX-011 for the treatment of advanced, refractory/resistant GPNMB-expressing breast cancer.

About Celldex Therapeutics, Inc.

Celldex Therapeutics is the first antibody-based combination immunotherapy company. Celldex has a pipeline of drug candidates in development for the treatment of cancer and other difficult-to-treat diseases based on its antibody focused Precision Targeted Immunotherapy Platform. The PTI Platform is a complementary portfolio of monoclonal antibodies, antibody-targeted vaccines and immunomodulators used in optimal combinations to create novel disease-specific drug candidates. For more information, please visit http://www.celldextherapeutics.com.

SOURCE: Celldex Therapeutics, Inc.