News Pressroom

October 13, 2005

MedImmune and Medarex Announce Filing of Investigational New Drug Application for Monoclonal Antibody for the Treatment of Lupus

GAITHERSBURG, Md., and PRINCETON, N.J., Oct. 13 /PRNewswire-FirstCall/ -- MedImmune, Inc. (Nasdaq: MEDI) and Medarex, Inc. (Nasdaq: MEDX) today announced the filing of an investigational new drug application (IND) with the U.S. Food & Drug Administration (FDA) for MEDI-545, a fully human monoclonal antibody (MAb) targeting interferon-alpha. Preclinical data indicate that levels of interferon-alpha are elevated in many patients with active systemic lupus erythematosus (SLE or lupus) and other autoimmune disorders, and may be associated with disease activity. MEDI-545 binds to interferon-alpha and has been shown to neutralize its activity in preclinical studies.

"This IND reflects MedImmune's commitment to the development of new treatments targeting inflammatory and autoimmune diseases, and marks another milestone in our efforts to advance our pipeline of product candidates," said Anthony J. Coyle, Ph.D., MedImmune's senior director, research, and head, inflammation biology. "The growing body of data about the role of interferons in lupus disease activity supports MedImmune's approach to using this target for developing therapies that may reduce the effects of SLE, a disease for which treatment options are currently limited."

In November 2004, MedImmune entered into a collaboration with Medarex to develop antibodies targeting interferon-alpha and the receptor to type I interferon, IFNAR1. The collaboration initially was 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 currently fully responsible for all ongoing development activities.

"We are pleased with the development progress to date for this product candidate as it advances toward clinical studies," said Donald L. Drakeman, Medarex's president and chief executive officer. "The entry of this antibody into a clinical program would mark the twenty-fifth antibody utilizing our UltiMAb(R) technology in clinical studies, and we are glad to be working with MedImmune toward this accomplishment."

Additional Information About MEDI-545

MEDI-545 is a fully human antibody that is believed to target multiple interferon-alpha subtypes. Preclinical data indicate that MEDI-545 may suppress the abnormal immune activity associated with lupus by binding to the pattern of multiple interferon-alpha subtypes seen in the serum of lupus patients. Further, preclinical studies have shown that an inhibition of interferon-alpha signaling corresponded to decreased autoantibody production and decreased disease activity, demonstrating the potential key role of interferon-alpha in a lupus disease animal model.

About Lupus

According to the Lupus Foundation of America, approximately 1.5 million Americans may suffer from some form of 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 drugs 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 MedImmune, Inc.

MedImmune strives to provide better medicines to patients, new medical options for physicians, rewarding careers to employees, and increased value to shareholders. Dedicated to advancing science and medicine to help people live better lives, the company is focused on the areas of infectious diseases, cancer and inflammatory diseases. With more than 2,000 employees worldwide, MedImmune is headquartered in Maryland. For more information, visit the company's website at http://www.medimmune.com.

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. Twenty-four of these therapeutic product candidates derived from Medarex technology are in human clinical testing, with two 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 http://www.medarex.com.

Except for the historical information presented herein, matters discussed herein may constitute forward-looking statements within the meaning of 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. 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 and MedImmune disclaim, 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 associated with the collaborative process, uncertainties related to product manufacturing as well as risks detailed from time to time in each company's respective public disclosure filings with the U.S. Securities and Exchange Commission (SEC), including their respective Annual Reports on Form 10-K for the fiscal year ended December 31, 2004 and subsequent Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. There can be no assurance that such development efforts will succeed, that such products will receive required regulatory approval or that, even if such regulatory approval were received, such products would ultimately achieve commercial success. Copies of public disclosure filings for MedImmune or Medarex are available from the companies' respective investor relations departments.

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

SOURCE MedImmune, Inc.

CONTACT:
Media:
Jamie Lacey, +1-301-398-4035
Kate Barrett, +1-301-398-4320
Investors:
Peter Vozzo, +1-301-398-4358
John Filler, +1-301-398-4086
all of MedImmune, Inc.
Media:
Jean Mantuano, +1-609-430-2880 x2221
Investors:
Laura S. Choi, +1-609-430-2880 x2216, both of Medarex, Inc.