Medarex, Inc.today announced a collaborative research agreement with Mitsubishi Pharma Corporation, a subsidiary of Mitsubishi Chemical Holdings Corporation.

PRINCETON, NJ, USA | May 31, 2007 | Medarex, Inc.(Nasdaq: MEDX) today announced a collaborative research agreement withMitsubishi Pharma Corporation, a subsidiary of Mitsubishi Chemical HoldingsCorporation. The two companies expect to generate and evaluate fully humanmonoclonal antibodies against a Mitsubishi target for the potential treatmentof autoimmune diseases. The companies plan to use Medarex’s UltiMAb HumanAntibody Development System(R) to generate antibodies for research andpossible development.

Under the terms of the agreement, Medarex and Mitsubishi Pharma will shareresearch responsibilities for any antibodies generated through thecollaboration. Other terms of the agreement were not disclosed.

"We are very much pleased to work with Medarex," said Dr. Tohru Nakajima,Executive Officer/Division Manager of the Pharmaceutical Research Division forMitsubishi Pharma. "We will gain access to excellent expertise that providesus with the potential advancement of novel therapeutics for autoimmunediseases."

"We are pleased to have this opportunity to partner with Mitsubishi PharmaCorporation and its research team and to work together to potentially discovernew antibody therapeutics," said Irwin Lerner, Interim President and CEO ofMedarex.

About Medarex, Inc.
Medarex is a biopharmaceutical company focused on the discovery,development and potential commercialization of fully human antibody-basedtherapeutics to treat life-threatening and debilitating diseases, includingcancer, inflammation, autoimmune disorders and infectious diseases. Medarexapplies its UltiMAb(R) technology and product development and clinicalmanufacturing experience to generate, support and potentially commercialize abroad range of fully human antibody product candidates for itself and itspartners. More than 30 of these therapeutic product candidates derived fromMedarex technology are in human clinical testing or have had INDs submittedfor such trials, with six of the most advanced product candidates currently inPhase III clinical trials. Medarex is committed to building value bydeveloping a diverse pipeline of antibody products to address the world’sunmet healthcare needs. For more information about Medarex, visit its websiteat www.medarex.com.

Statement on Cautionary Factors
For Medarex: Except for the historical information presented herein,matters discussed herein may constitute forward-looking statements that aresubject to certain risks and uncertainties that could cause actual results todiffer materially from any future results, performance or achievementsexpressed or implied by such statements. Statements that are not historicalfacts, including statements preceded by, followed by, or that include thewords "potential"; "believe"; "anticipate"; "intend"; "plan"; "expect";"estimate"; "could"; "may"; or similar statements are forward-lookingstatements. Medarex disclaims, however, any intent or obligation to updatethese forward-looking statements. Risks and uncertainties include risksassociated with product discovery and development and uncertainties related tothe implementation of the collaborative research agreement with MitsubishiPharma Corporation as well as risks detailed from time to time in Medarex’spublic disclosure filings with the U.S. Securities and Exchange Commission(SEC), including its Annual Report on Form 10-K for the fiscal year endedDecember 31, 2006. There can be no assurance that such development effortswill succeed or that other developed products will receive required regulatoryclearance or that, even if such regulatory clearance were received, suchproducts would ultimately achieve commercial success. Copies of Medarex’spublic disclosure filings are available from its investor relationsdepartment.

Medarex(R), the Medarex logo and UltiMAb(R) are registered trademarks ofMedarex, Inc. All rights are reserved.

SOURCE Medarex, Inc.