News Pressroom

June 20, 2005

MedImmune and Avalon Pharmaceuticals Announce Collaboration to Discover Small Molecule Therapeutic Drugs for Inflammatory Diseases

GAITHERSBURG, Md. and GERMANTOWN, Md., June 20 /PRNewswire-FirstCall/ -- MedImmune, Inc. (Nasdaq: MEDI) and Avalon Pharmaceuticals, Inc. today announced a collaboration to discover and develop small molecule therapeutic compounds in the area of inflammatory disease. Avalon will use its AvalonRx(TM) drug discovery engine to identify lead compounds. MedImmune will be responsible for preclinical and clinical testing of any resulting product candidates, as well as all future development and sales and marketing activities.

Under the terms of the agreement, Avalon will receive an upfront payment, research and development support, milestone payments and royalties on any future marketed products. MedImmune also has the option to initiate two additional small molecule drug discovery collaborations with Avalon under similar terms.

"This collaboration with Avalon expands the breadth of our research to include small molecules as potential therapies for various inflammatory diseases," stated Edward T. Mathers, MedImmune's senior vice president of corporate development. "We look forward to investigating Avalon's proprietary drug discovery technology with the hope that our combined efforts will lead to developing new treatment options for patients suffering from debilitating disease."

"We are excited to be MedImmune's first partner in the discovery and optimization of small molecule therapeutic compounds," stated Ken Carter, Avalon's chief executive officer. "It is also significant that this is our first major program with our AvalonRx drug discovery platform in a therapeutic area beyond our internal cancer focus."

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 approximately 2,000 employees worldwide, MedImmune is headquartered in Maryland. For more information, visit the company's website at http://www.medimmune.com.

About Avalon

Avalon Pharmaceuticals is a biopharmaceutical company focused on the discovery and development of small molecule therapeutics for the treatment of cancer. Avalon seeks to discover and develop novel therapeutics through the use of a comprehensive, innovative and proprietary suite of technologies based upon large-scale gene expression analysis which it calls AvalonRx(TM). Avalon Pharmaceuticals was established in 1999 and is headquartered in Germantown, Maryland.

This announcement contains, in addition to historical information, certain forward-looking statements that involve risks and uncertainties, in particular, related to the research and development of future small molecule products. Such statements reflect the current views of MedImmune and/or Avalon management 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. There can be no assurance that such development efforts will succeed, that the products will receive required regulatory clearance or, even if such regulatory clearance is received, that the subsequent products will ultimately achieve commercial success.

SOURCE MedImmune, Inc.

CONTACT:
Investors:
Peter Vozzo, +1-301-398-4358
John Filler, +1-301-398-4086
both of MedImmune, Inc.
Gary Lessing, Chief Financial Officer
Avalon Pharmaceuticals, Inc.
+1-301-556-9828
Emily Poe, Vice President of Noonan Russo
+1-646-342-3795
for Avalon Pharmaceuticals, Inc.