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PRINCETON, N.J., Dec. 8 /PRNewswire-FirstCall/ -- Medarex, Inc. (Nasdaq: MEDX) announced today results from a preclinical study for MDX-1401, a second-generation non-fucosylated version of MDX-060 that targets CD30, a marker for activated lymphocytes that is present on the malignant cells of Hodgkin's lymphoma (HL) as well as other CD30-expressing cancers. MDX-1401 demonstrated almost a doubling in potency and efficacy in cell lines when compared to MDX-060. The improved potency and efficacy of MDX-1401 in in vivo xenograft models indicates enhanced antibody-dependent cellular cytotoxicity (ADCC) activity, an important mechanism of action of therapeutic antibodies. In addition to anti-tumor activity, the preclinical data showed a statistically significant increase in median survival time for the MDX-1401 treatment group when compared to the MDX-060 treatment group.

The data were presented in a poster presentation entitled "Characterization of MDX-1401, a human anti-CD30 antibody with enhanced effector function, for therapy of malignant lymphoma" (abstract #1580) at the 50th Annual Meeting of the American Society of Hematology (ASH) being held December 6-9, 2008 in San Francisco, CA.

"We are excited with the growing body of scientific evidence that indicates enhanced ADCC and improved anti-tumor efficacy with the second generation anti-CD30 antibody, MDX-1401, as compared to MDX-060," said Geoffrey M. Nichol, MBChB, Senior Vice President of Product Development at Medarex. "The data we have seen to date continues to inform our development plans and underscores the importance of assessing MDX-1401 as a potentially more potent therapeutic for CD-30 expressing malignancies. We look forward to presenting results from the ongoing Phase 1 MDX-1401 study and the recently completed Phase 2 MDX-060 study in 2009."

More information about the ASH Annual Meeting may be found at www.hematology.org

About MDX-1401

MDX-1401 is a non-fucosylated version of the MDX-060 antibody and is enhanced for greater antibody-dependent cellular cytotoxicity (ADCC) activity, an important function of the human immune system, whereby immune cells can kill target cells. ADCC activity is one important mechanism underlying the efficacy of some currently approved anti-cancer antibodies. A dose-escalation, multi-dose Phase 1 clinical trial of MDX-1401 in up to 36 patients with relapsed or refractory Hodgkin's lymphoma (HL) is currently ongoing, with results expected in 2009. The trial is designed to establish and evaluate the safety profile and initial efficacy of the antibody.

About Medarex

Medarex is a biopharmaceutical company focused on the discovery, development and potential commercialization of fully human antibody-based therapeutics to treat life-threatening and debilitating diseases, including cancer, inflammation, autoimmune disorders and infectious diseases. Medarex applies its UltiMAb(R) technology and product development and clinical manufacturing experience to generate, support and potentially commercialize a broad range of fully human antibody product candidates for itself and its partners. Over forty of these therapeutic product candidates derived from Medarex technology are in human clinical testing or have had INDs submitted for such trials, with the most advanced product candidates currently in Phase 3 clinical trials or the subject of regulatory applications for marketing authorization. Medarex is committed to building value by developing a diverse pipeline of antibody products to address the world's unmet healthcare needs. For more information about Medarex, visit its website at www.medarex.com.

Medarex Statement on Cautionary Factors

Except for the historical information presented herein, the statements relating to MDX-1401 in this press release may constitute forward-looking statements, as defined in the Private Securities Litigation Reform Act of 1995, that are subject to certain risks and uncertainties that could cause actual results to differ materially from any future results, performance or achievements expressed or implied by such statements. Medarex disclaims, however, any intent or obligation to update these forward-looking statements. Risks and uncertainties include risks associated with product discovery and development of MDX-1401, as well as risks detailed from time to time in Medarex's public disclosure filings with the U.S. Securities and Exchange Commission (SEC), including its Annual Report on Form 10-K for the fiscal year ended December 31, 2007 and its quarterly reports on Form 10-Q. Copies of Medarex's public disclosure filings are available from its investor relations department.

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