57% of patients in trial achieve a 50% or more reduction in disease activity

Copenhagen, Denmark and Princeton, NJ, US; December 21, 2004 – Genmab A/S (CSE: GEN) and Medarex, Inc. (Nasdaq: MEDX) announced today encouraging safety and efficacy data from a Phase I/II trial using HuMax™-Inflam/MDX-018 to treat patients suffering from an autoimmune disease. Details concerning the disease indication are not being disclosed at this time.

Fifty-seven percent, or 16 of 28, patients who completed the study achieved a 50% or more reduction, compared with baseline, in the primary endpoint measure of disease activity one week after final dosing, at week 8. In the highest dose group (8/4 mg/kg) all 7 patients saw a 50% or more reduction in disease activity. At the timepoint of one week after the initial dose, 14 patients were seen to achieve a 50% or more reduction in disease activity with 5 out of 7 patients in the highest dose group seeing this level of disease improvement.

In a pooled analysis of all dose groups after eight weeks, a statistically significant mean reduction in disease activity of 56% was seen.

Neither serious adverse event reported (one event of syncope and one event of acute myocardial infarction) were determined by the investigator to be related to HuMax-Inflam/MDX-018. No dose limiting toxicity was reported after administration of doses up to 8 mg/kg, and it is believed that the maximum tolerated dose was not reached.

HuMax-Inflam/MDX-018, a fully human antibody developed using Medarex’s UltiMAb® technology, is being developed jointly by Genmab and Medarex. Genmab and Medarex are investigating potential development paths, and also the commercial opportunities for this product at present.

About the Trial
In this non-placebo controlled, ascending dose Phase I/II clinical trial, a total of 31 patients received an initial single dose of 0.15, 0.5, 1, 2, 4, or 8 mg/kg of HuMax-Inflam/MDX-018. Following a satisfactory safety review, 29 patients entered a repeat dose extension study receiving four doses at weekly intervals.

About Medarex, Inc.
Medarex is a biopharmaceutical company focused on the discovery and development of fully human antibody-based therapeutics to treat life-threatening and debilitating diseases, including cancer, inflammation, autoimmune and infectious diseases. Medarex applies its UltiMAb® technology and product development and clinical manufacturing experience to generate, support and potentially commercialize a broad range of fully human antibody products for itself and its partners. Twenty-one of these therapeutic products derived from Medarex technology are currently in human clinical testing, with the most advanced product presently in a Phase III clinical trial. 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.

For Medarex: Except for the historical information presented herein, matters discussed herein may constitute forward-looking statements 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. Statements that are not historical facts, including statements preceded by, followed by, or that include the words “potential”; “believe”; “anticipate”; “intend”; “plan”; “expect”; “estimate”; “could”; “may”; or similar statements are forward-looking 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, uncertainties related to the outcome of clinical trials, slower than expected rates of patient recruitment, unforeseen safety issues resulting from the administration of MDX-018 in patients, uncertainties related to product manufacturing 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, 2003 and subsequent Quarterly Reports on Form 10-Q. There can be no assurance that such development efforts will succeed, that MDX-018 or other developed products will receive required regulatory clearance or that, even if such regulatory clearance were received, such products would ultimately achieve commercial success. Copies of Medarex’s public disclosure filings are available from its investor relations department.

Medarex®, the Medarex logo and UltiMAb® are registered trademarks of Medarex, Inc. All rights are reserved. UltiMAb® is a registered trademark of Medarex, Inc. All rights are reserved. HuMax™ is a trademark of Genmab A/S. All rights are reserved.