News Pressroom

September 16, 2003

FDA Approves Expanded Label for Synagis(R) Use In Children with Congenital Heart Disease (CHD)

GAITHERSBURG, Md., Sep 16, 2003 /PRNewswire-FirstCall via COMTEX/ -- MedImmune, Inc. (Nasdaq: MEDI) today announced that the U.S. Food & Drug Administration (FDA) has approved the addition of new safety and efficacy data to the prescribing information of Synagis(R) (palivizumab). In what is the largest study conducted in children with complex congenital heart disease, investigators' findings supported the drug's use in young children with hemodynamically significant CHD to prevent hospitalization caused by respiratory syncytial virus (RSV). RSV is the most common cause of lower tract respiratory infections in infants and children worldwide, typically occurring during the fall and winter months.

"Infants and young children with significant CHD are at high risk of serious RSV disease," said Dr. Edward M. Connor, MedImmune's senior vice president, clinical development. "We are pleased that the FDA has expanded the label for Synagis to help protect these patients from a potentially life- threatening RSV infection."

Congenital heart defects are structural problems of the heart that are present at birth, having occurred during development. Approximately 32,000 children are born in the U.S. each year with CHD, of which there are many different types with varying degrees of severity. Children born with serious CHD who have decreased cardiac or pulmonary reserve appear to be at highest risk of serious RSV infection. These children have been shown to require intensive care and use mechanical ventilation with RSV infection more frequently than children who do not have CHD. Further, children with CHD who are hospitalized with RSV have a fatality rate that is two to six times greater than those without CHD.

Synagis is a humanized monoclonal antibody licensed by the FDA in 1998 to prevent serious lower respiratory tract disease caused by RSV in pediatric patients at high risk of RSV disease. MedImmune submitted data to the FDA in November 2002 from its large, multinational Phase 3 clinical study indicating that Synagis was safe and effective in preventing RSV-related hospitalizations in young children with hemodynamically significant CHD.

"Synagis is an important preventative option for children with significant congenital heart disease," said Dr. Henry M. Sondheimer, professor of pediatrics, University of Colorado Health Sciences Center and clinical director of Pediatric Cardiology at The Children's Hospital, Denver. "Children with CHD who are hospitalized with RSV have substantially higher rates of morbidity and mortality than those children who do not have CHD. With the FDA's approval of CHD information in the Synagis label, pediatricians and pediatric cardiologists will have a better understanding of those vulnerable children who will most benefit from RSV prophylaxis with Synagis."

The regulatory submission was based on a four-year, double-blind, placebo- controlled study assessing 1,287 children less than two years of age with serious CHD. In the study, children were randomized to receive monthly intramuscular injections (15 mg/kg) of either Synagis (n=639) or placebo (n=648) during four consecutive RSV seasons. The study was conducted at 76 centers in North America, France, Germany, Poland, Sweden, and the United Kingdom and was completed in 2002. The Synagis group had 45 percent relative reduction in hospitalizations due to RSV (p=0.003) compared to the placebo group, with a total of 34 patients compared to 63 patients requiring hospitalization. The adverse events reported in the two treatment groups were similar.

For children with chronic lung disease, premature infants who are less than 36 weeks gestational age, and children with significant CHD, clinical studies now have demonstrated that Synagis is safe and effective at preventing serious RSV-related hospitalizations.

In July 2003, Abbott Laboratories, international distributor for Synagis, announced that the European Agency for the Evaluation of Medicinal Products had granted a positive opinion for Synagis use in young children born with CHD to prevent respiratory tract infection caused by RSV.

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, 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.

Media: Jamie Lacey, +1-240-632-4035, or Investors: Will
Roberts, +1-301-527-4358, both of MedImmune, Inc.
http://www.medimmune.com