Celldex Therapeutics, Inc. (Nasdaq: CLDX) today announced that new preclinical data on its therapeutic antibody program, CDX-1127, was presented in a poster presentation at the 2011 American Society of Hematology (ASH) 53rd Annual Meeting in San Diego, CA. The presentation (poster #2861), entitled “Development of a Human Anti-CD27 Antibody with Efficacy in Lymphoma and Leukemia Models by Two Distinct Mechanisms,” describes proof of concept studies for CDX-1127 in preclinical models of lymphoma. CDX-1127 is a novel therapeutic antibody candidate that is currently being evaluated in a Phase 1 dose escalation clinical trial as a treatment for patients with hematologic malignancies and selected solid tumors.

CDX-1127 is a fully human monoclonal antibody targeting CD27, a member of the tumor necrosis factor (TNF) receptor superfamily with a critical role in the balance between immunity and tolerance. Agonist anti-CD27 antibodies have been shown to effectively activate immune cells to control or eliminate lymphomas in mouse models. CD27 is also expressed at high levels on several types of B and T cell malignancies and can also function as a target for direct activity by anti-CD27 antibodies with effector function.

“Based on a growing body of information, we believe the CD27 pathway is a unique opportunity for intervention with an appropriate agonist antibody,” said Tibor Keler, Ph.D., Celldex’s Chief Scientific Officer. “The preclinical data provide great encouragement for CDX-1127 in lymphomas and selected solid tumor indications and in combination with other therapies.”

In this presentation, CDX-1127 displayed both mechanisms of action in demonstrating the ability to activate immune cells and directly target CD27 on the cell surface of the tumor, with the following key findings:

• CDX-1127 is a potent agonist of CD27 when combined with T cell receptor stimulation;
• CDX-1127 mediates significant anti-tumor efficacy when tested in several models of human lymphoblastic tumors grown in immune-deficient mice (effector function);
• CDX-1127 mediates significant anti-tumor efficacy in immune-competent mouse models of murine lymphoma (immune activation function);
• CDX-1127 demonstrated a good safety profile in preclinical safety.

“This is a very exciting program for Celldex, as the preclinical data suggest that CDX-1127 may represent two therapeutic strategies in one - both immune activation and direct tumor targeting depending on the indication,” said Tom Davis, M.D., Chief Medical Officer of Celldex Therapeutics. “Either approach alone has generated successful drugs.”

About CDX-1127

CDX-1127 is a human monoclonal antibody program targeting CD27, a member of the tumor necrosis factor (TNF) receptor superfamily. CD27 is a critical molecule in the activation pathway of lymphocytes. It acts downstream from CD40 and may provide a novel way to regulate the immune responses. CD27 is a co-stimulatory molecule on T cells and is over-expressed in certain lymphomas and leukemias. CDX-1127 has two mechanisms of action: immune activation and effector function. Previously published data by Professor Martin Glennie, Ph.D., Director of Cancer Sciences, Tenovus Research Laboratory, University of Southampton, UK, has demonstrated that targeting CD27 with monoclonal antibodies in mice is highly effective at promoting anti-cancer immunity. Celldex presented more recent preclinical in vitro and animal data with CDX-1127 at the 2011 American Association for Cancer Research (AACR) 101st Annual Meeting demonstrating that targeting CD27 receptors with CDX-1127 antibodies can increase the numbers of responding T cells and can directly impact tumor cells expressing CD27.

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-1307, CDX-011, CDX-1135 (formerly TP10), CDX-1401, CDX-1127, 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 TechnologyTM 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.