Celldex Completes Accrual of CDX-011 Phase 2b "EMERGE” Study in Advanced Breast Cancer

Celldex Therapeutics, Inc. (Nasdaq: CLDX) today announced that it has completed accrual of the EMERGE study, a randomized Phase 2b study evaluating CDX-011 (glembatumumab vedotin) in patients with previously treated metastatic or locally advanced breast cancer. The Company anticipates presenting results at an appropriate scientific conference in the first half of 2012.

"The median survival of patients with metastatic breast cancer is two to three years and for patients with "triple-negative" disease, the prognosis is even more grim,” said Thomas Davis, MD, Chief Medical Officer of Celldex Therapeutics. "A previous Phase 1/2 single arm study of CDX-011 demonstrated encouraging results in women whose tumors express GPNMB, a molecule associated with worse outcome. These results included disease regression and improvements in progression free survival (PFS) compared to historical controls. We are very pleased with the rapid accrual of this study and expect the data will continue to support the potential of CDX-011 as a much needed new treatment option for patients facing these difficult to treat breast cancers.”

CDX-011 is an antibody-drug conjugate targeting glycoprotein NMB (GPNMB) which is over expressed in several cancers including breast cancer, melanoma, lymphomas/leukemias and squamous carcinoma of the lung. The randomized, multi-center, controlled trial enrolled advanced and heavily pre-treated breast cancer patients who are unlikely to benefit from any approved therapies and whose tumors are confirmed to express GPNMB via a 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 were randomized (2:1) to receive either CDX-011 or single-agent "Investigator’s Choice” chemotherapy. Patients randomized to receive Investigator’s Choice are allowed to cross-over to CDX-011 following disease progression. Activity endpoints include response rate (RR) and PFS. The study is being conducted at approximately 20 academic and community sites across the U.S.

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 were 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 have 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 breast cancer and 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 well tolerated 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 (PTI) 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.

Safe Harbor Statement Under the Private Securities Litigation Reform Act of 1995: This release contains "forward-looking statements” made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995, including those related to the Company’s strategic focus and the future development and commercialization (by Celldex and others) of rindopepimut (CDX-110), CDX-011, CDX-1135 (formerly TP10), CDX-1401, CDX-1127, CDX-301, Belinostat and other products. Forward-looking statements reflect management's current knowledge, assumptions, judgment and expectations regarding future performance or events. Although management believes that the expectations reflected in such statements are reasonable, they give no assurance that such expectations will prove to be correct and you should be aware that actual results could differ materially from those contained in the forward-looking statements. Forward-looking statements are subject to a number of risks and uncertainties, including, but not limited to, our ability to obtain additional capital on acceptable terms, or at all, including the additional capital which will be necessary to complete the clinical trials that we plan to initiate in 2011; our ability to adapt APC Targeting Technology^TM to develop new, safe and effective vaccines against oncology and infectious disease indications; our ability to successfully complete product research and further development of our programs; the uncertainties inherent in clinical testing; our limited experience in bringing programs through Phase 3 clinical trials; our ability to manage research and development efforts for multiple products at varying stages of development; the timing, cost and uncertainty of obtaining regulatory approvals; the failure of the market for the Company's programs to continue to develop; our limited cash reserves and our ability to obtain additional capital on acceptable terms, or at all; our ability to protect the Company’s intellectual property; the loss of any executive officers or key personnel or consultants; competition; changes in the regulatory landscape or the imposition of regulations that affect the Company’s products; and other risks detailed from time to time in the Company's filings with the Securities and Exchange Commission, including the Company's Form 10-K for the fiscal year ended December 31, 2010, and its Forms 10-Q and 8-K.

All forward-looking statements are expressly qualified in their entirety by this cautionary notice. You are cautioned not to place undue reliance on any forward-looking statements, which speak only as of the date of this release. We have no obligation, and expressly disclaim any obligation, to update, revise or correct any of the forward-looking statements, whether as a result of new information, future events or otherwise.