PRINCETON, N.J.; January 19, 2006

Medarex Announce NovImmune Filing of Investigational New Drug Application for Fully Human Antibody for the Treatment of Autoimmune Disease

29th UltiMAb® product triggers milestone payment

Princeton, N.J.; January 19, 2006 - Medarex, Inc. (Nasdaq: MEDX) today announced the filing of an Investigational New Drug (IND) application in the Netherlands by its licensing partner, NovImmune SA, for NI-0401, a fully human antibody that targets the CD3 antigen, for the treatment of autoimmune disease. The antibody product was developed using Medarex's UltiMAb® technology. Medarex expects to receive an undisclosed milestone payment and may receive future milestone payments and royalties should this product candidate progress through clinical development.

"We are pleased with the progress that our partner, NovImmune, has achieved in filing an IND," said Donald L. Drakeman, President and CEO of Medarex, Inc. "With the advancement of the NovImmune antibody into clinical trials, there are now twenty-nine fully human antibodies generated from Medarex's technology that are in clinical development by Medarex and its partners."

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® 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. Twenty-nine of these therapeutic product candidates derived from Medarex technology are in human clinical testing testing or have had INDs submitted for such trials, with four of the most advanced product candidates currently in Phase III clinical trials. 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.

About NovImmune
NovImmune is a Geneva, Switzerland, based product development company focusing on immune mechanisms in order to clinically impact Immune Related Diseases, Inflammation and Organ transplantation. NovImmune has a portfolio of fully human therapeutic monoclonal antibodies in development, including NI-0401, the first fully human antibody against CD3. NI-0401 may prove beneficial in a series of inflammatory and autoimmune diseases, and may induce long-term immune tolerance, which would allow control of such diseases over an extended period of time. In addition, NovImmune has a second fully human monoclonal antibody that targets interferon-gamma (NI-0501), currently in GMP production. NovImmune generates its fully human monoclonal antibodies in house using either transgenic mouse lines (licensed from Medarex) or antibody display technology (licensed from Cambridge Antibody Technology).

Statement on Cautionary Factors
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 antibody products in patients, uncertainties related to product manufacturing, risks associated with the use of hazardous substances 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, 2004 and subsequent Quarterly Reports on Form 10-Q. There can be no assurance that such development efforts will succeed or that 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.

Contacts:

NovImmune SA
Jack Barbut, ScD.
CEO
Phone: +41 22 593 51 14

Medarex, Inc.
Laura S. Choi
Investor Relations
Phone: +1-609-430-2880, x2216

Jean Mantuano
Corporate Communications (media)
Phone: +1-609-430-2880, x2221