News Pressroom

November 20, 2003

MedImmune Demonstrates Proof of Principle for Targeting EphA2 Protein Overexpressed on Cancer Cells

Study Published in Cancer Research First to Show Anti-Cancer Activity In Animals Using Antibodies Aimed at EphA2

GAITHERSBURG, Md., Nov. 20 /PRNewswire-FirstCall/ -- MedImmune, Inc. (Nasdaq: MEDI) scientists today published in the November 15 issue of Cancer Research that preclinical studies in animals demonstrated proof of principle for using antibodies targeting the protein EphA2 as a potential treatment for certain cancers.

EphA2 is a protein overexpressed by many different types of human cancers, including melanoma (skin cancer), breast cancer and prostate cancer. The highest levels of EphA2 have been found on the most aggressive cancer cells, which is consistent with evidence linking EphA2 with clinical features of metastasis (cancer's spread). Early research indicates that EphA2 functions differently on malignant cells than it does on normal cells. On malignant cells, EphA2 appears to promote tumor growth, survival and invasiveness.

"Using anti-EphA2 antibodies, we may be able to selectively destroy tumor cells while minimizing the damage to normal cells," said Peter Kiener, D.Phil., vice president, research at MedImmune. "These therapeutic antibodies could provide a much-needed option for treating many forms of cancer that are otherwise resistant to conventional therapies."

Data from the Cancer Research study, entitled "Differential EphA2 Epitope Display on Normal versus Malignant Cells," showed that certain antibody- binding sites on EphA2 are selectively available on cancerous cells, but are not accessible on normal cells. The study also showed that delivering anti- EphA2 antibodies at a level of 6 mg/kg dose results in substantial decreases in tumor growth in vivo (in mice models). Should additional preclinical studies continue to exhibit comparable results, MedImmune anticipates filing an Investigational New Drug application (IND) with the U.S. Food & Drug Administration (FDA) in early 2005 to begin testing in people.

Expanding the MedImmune Oncology Pipeline

MedImmune in-licensed the worldwide rights to EphA2 technology from Purdue Research Foundation in October 2001. Since then, MedImmune has continued to build a body of scientific evidence demonstrating the role of EphA2 in uncontrolled tumor growth and metastasis, as well as the potential for anti- EphA2 antibodies to specifically treat certain cancers.

Since February 1999, when MedImmune acquired Vitaxin(R), its first cancer- related product candidate, MedImmune has been selectively building its oncology organization and pipeline. The company's goal is to become a world leader in the development and marketing of cancer-related therapies. Currently, MedImmune has a 70-person oncology sales and marketing organization detailing Ethyol(R) (amifostine) to oncologists throughout the United States. MedImmune's research and development organization is advancing and expanding the focus of a number of internal product candidates through melanoma and prostate cancer studies with Vitaxin, non-small cell lung cancer and acute myelogenous leukemia (AML) studies with Ethyol, and T cell lymphoma studies with siplizumab. In addition, since October 2001, MedImmune's internal discovery and in-licensing activities have successfully expanded the company's preclinical pipeline with six new oncology-related technologies or targets.

About MedImmune, Inc.

MedImmune is a leading biotechnology company focused on researching, developing and commercializing products to prevent or treat infectious disease, autoimmune disease and cancer. MedImmune actively markets four products, Synagis(R) (palivizumab), FluMist(TM) (Influenza Virus Vaccine Live, Intranasal), Ethyol(R) (amifostine) and CytoGam(R) (cytomegalovirus immune globulin intravenous (human)), and has additional products in clinical testing. MedImmune employs approximately 1,700 people, is headquartered in Gaithersburg, Maryland, and has additional operations in Frederick, Maryland, as well as Pennsylvania, California, the United Kingdom and the Netherlands. For more information on the company and its products, visit MedImmune's website at www.medimmune.com.

This announcement may contain, in addition to historical information, certain forward-looking statements that involve risks and uncertainties. Such statements reflect management's current views and are based on certain assumptions. Actual results could differ materially from those currently anticipated as a result of a number of factors, including risks and uncertainties discussed in MedImmune's filings with the U.S. Securities and Exchange Commission. The company is developing several products for potential future marketing. There can be no assurance that such development efforts will succeed, that such products will receive required regulatory clearance or that, even if such regulatory clearance were received, such products would ultimately achieve commercial success.

SOURCE MedImmune, Inc.

CONTACT: Media: Jamie Lacey, +1-240-632-4035, or for Investors: Will Roberts, +1-301-527-4358, or John Filler, +1-240-632-4086, all of MedImmune, Inc.

/Web site: http://www.medimmune.com/