Medarex, Inc. announced today that its partner MedImmune, Inc. has initiated a Phase Ib multi-dose clinical trial of MEDI-545 for the potential treatment of systemic lupus erythematosus

PRINCETON, NJ, USA | July 19, 2007 | Medarex, Inc. (Nasdaq: MEDX) announced today that its partner MedImmune, Inc. has initiated a Phase Ib multi-dose clinical trial of MEDI-545 for the potential treatment of systemic lupus erythematosus (SLE or lupus).

MEDI-545 is a fully human antibody generated by Medarex’s UltiMAb Human Antibody Development System(R).

MedImmune is also evaluating MEDI-545 in a Phase I single-dose trial in lupus patients and a Phase I dose-escalation trial in psoriasis patients. Preliminary data from the Phase I single-dose trial in lupus showed an acceptable safety profile and tolerability of MEDI-545 in patients, as presented at the 8th International Lupus Consortium, held May 24-26, 2007 in Shanghai.

MedImmune plans to begin an additional trial for MEDI-545 in idiopathic inflammatory myositis, an immunological disease that involves chronic muscle inflammation, pain and weakness.

"We are pleased with the advances that MedImmune continues to make in the development of MEDI-545.

We believe that the ongoing studies as well as studies in new indications hold the promise of delivering new therapeutic options to patients living with autoimmune diseases," said Howard H. Pien, President and CEO of Medarex.

About MEDI-545

MEDI-545 (previously known as MDX-1103) is a fully human monoclonal antibody targeting interferon-alpha. Published data indicate that levels of interferon-alpha are elevated in many patients with active SLE and other autoimmune disorders, and may be associated with disease activity. Preclinical data from animal models suggest that MEDI-545 may suppress the abnormal immune activity associated with lupus by binding to multiple interferon-alpha subtypes seen in the serum of lupus patients.

In November 2004, MedImmune entered into a collaboration with Medarex to focus on two specific antibodies, one of which was MDX-1103 (now known as MEDI-545). Under the terms of the agreement, MedImmune is responsible for all ongoing clinical development activities. Prior to the beginning of pivotal studies, Medarex may elect to co-develop the products in return for the opportunity to co-promote and to receive a share of the commercial profits in the United States. In all other cases, Medarex will be entitled to receive milestone payments and royalties.

About Lupus
Approximately 350,000 individuals in the United States are affected with lupus, a chronic inflammatory disease that causes the body to attack its own tissues and organs, including the skin, joints, blood and kidneys. Treatments for lupus include anti-inflammatory drugs, antimalarials, corticosteroids and drugs approved for other purposes, such as immunosuppressive agents given to cancer patients undergoing chemotherapy or medicines developed to treat arthritis patients. Lupus occurs about 10 times more frequently in adult females than adult males, and is two to three times more common among African Americans, Hispanics, Asians and Native Americans.

About Medarex, Inc.
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. More than 30 of these therapeutic product candidates derived from Medarex technology are in human clinical testing or have had INDs submitted for such trials, with seven 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 .

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 uncertainties related to the outcome of clinical trials, slower than expected rates of patient recruitment, unforeseen safety issues resulting from the administration of MEDI-545 in patients, risks relating to MedImmune, Inc. deciding to stop or delay future clinical development with respect to MEDI-545, to stop or delay the Phase I clinical trial, or to stop or delay future trials relating to MEDI-545 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, 2006.

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

SOURCE: Medarex, Inc