Antibody Targeting the Interleukin-5 Receptor Shows Evidence of Biological Activity

GAITHERSBURG, MD, USA | July 23, 2007 | MedImmune, Inc. today announced the presentation of interim clinical study data suggesting that its monoclonal antibody (MAb) targeting the interleukin-5 (IL-5) receptor is well-tolerated and shows evidence of biological activity in a Phase 1 study of adults with mild asthma. These data, along with preclinical results shedding further light on the antibody’s mechanism of action and potency, were presented during the International Eosinophil Society 5th Biennial Symposium (IES), held July 18-22 in Snowbird, Utah.

Preliminary results from the Phase 1 study, conducted to assess the safety and biological activity of the anti-IL-5 receptor MAb, suggest that the antibody-dependent cellular cytotoxicity (ADCC) enhanced molecule successfully depleted eosinophils, a class of white blood cells implicated in the pathology of asthma and other inflammatory diseases. In addition to direct depletion of eosinophils, the MAb also aims to neutralize the activity of IL-5, which is believed to play a key role in the growth and development of eosinophils.

"We are very encouraged by the results to date from this Phase 1 study with this novel antibody," said Barbara White, M.D., MedImmune’s vice president, clinical development, inflammatory disease. "The initial data from this trial suggest that our efforts to not only inhibit the cytokine involved in eosinophil production, but to actually directly deplete eosinophils, may offer a viable therapeutic approach to developing new treatments for patients with asthma."

The preclinical data presented at IES provided new insight to the molecule’s mechanism of action and potency, showing that in vitro, the antibody effectively kills cells expressing the IL-5 receptor. Previous attempts to develop IL-5-targeted therapies in asthma have lacked efficacy, attributable to an incomplete depletion of eosinophils in lung tissue. However, the anti-IL-5 receptor antibody shows potential to address that issue through its ability to both inhibit interaction of IL-5 with its receptor and actually deplete cells expressing the IL-5 receptor through enhanced ADCC activity.

About Anti-IL-5 Receptor MAb
MedImmune and Biowa, Inc. entered into a licensing and collaboration agreement to develop and commercialize new inflammatory disease therapies targeting the IL-5 receptor in December 2006. The MAb, developed utilizing BioWa’s POTELLIGENT(R) technology platform for the development of ADCC-enhanced antibodies, has been shown to neutralize IL-5 activity and to deplete eosinophils in preclinical studies. Preclinical research also suggests that depletion of eosinophils by inhibiting IL-5 may result in reduced airway inflammation, airway hyper-responsiveness (AHR) and mucous secretion.

About POTELLIGENT(R) Technology
POTELLIGENT(R) Technology improves potency and efficacy of antibody therapeutics, by enhancing antibody-dependent cellular cytotoxicity (ADCC), one of the major mechanism of antibody therapeutics. Research shows that POTELLIGENT(R) Technology significantly enhances ADCC activity of an antibody in vitro, thereby increasing the potential for improved activity in vivo.

About Asthma
Asthma is a chronic disease of the airways that may cause wheezing, breathlessness, chest tightness and coughing. According to the U.S. Centers for Disease Control and Prevention (CDC), more than 20 million Americans reported having asthma in 2001, including more than six million children. In 2000, the CDC reported that there were more than 10 million asthma-related outpatient visits to private physician offices and hospital clinics (nearly 5 million of these involved children under 18). The National Institutes of Health (NIH) have estimated asthma-related healthcare costs in the U.S. at $14 billion annually.

About MedImmune, Inc.

MedImmune strives to provide better medicines to patients, new medical options for physicians and rewarding careers to employees. Dedicated to advancing science and medicine to help people live better lives, the company is focused on the areas of infectious disease, cancer and inflammatory disease. With approximately 3,000 employees worldwide, MedImmune is headquartered in Maryland. For more information, visit the company’s website at http://www.medimmune.com.

SOURCE: MedImmune, Inc.