News Pressroom

September 30, 2003

MedImmune Expands Intranasal Vaccine Program

Preclinical Study Published in Journal of Virology Shows
Intranasal Vaccine Technology Induces Protective Immune
Response Against Three Serious Respiratory Viruses

GAITHERSBURG, Md., Sept. 30 /PRNewswire-FirstCall/ -- MedImmune, Inc. (Nasdaq: MEDI) today announced that it had induced a protective immune response against three of the most serious childhood respiratory viruses in a study incorporating intranasal vaccine technology similar to that used to develop FluMist(TM) (Influenza Virus Vaccine Live, Intranasal). FluMist is the first nasally delivered influenza vaccine available in the United States. The results of the preclinical study involving parainfluenza virus type 3 (PIV3), respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) were published in the October issue of the Journal of Virology.

"Today, there are no approved vaccines to prevent RSV, hMPV, or PIV3 -- three viruses responsible for extensive respiratory illness, and even death, in young children," said Richard Spaete, Ph.D., senior research director at MedImmune. "Based upon our early results, it appears that we may be able to prevent diseases due to these multiple respiratory viruses with a single vaccine using intranasal vaccine technology. If successful, such a product may give the medical community a new, needle-free option in helping to keep young children healthy."

The Journal of Virology study showed that a combination of the bovine and human versions of PIV3 could be successfully constructed as a carrier to induce a protective immune response against PIV3 and either RSV or hMPV. In the study, entitled "Effects of Human Metapneumovirus and Respiratory Syncytial Virus Antigen Insertion in Two 3-Prime Proximal Genome Positions of Bovine/Human Parainfluenzavirus Type 3 on Virus Replication and Immunogenicity," animals immunized with a combination of either PIV3 and RSV or PIV3 and hMPV were protected from the relevant viruses in challenge studies and produced neutralizing antibodies against the viruses.

MedImmune is now conducting additional preclinical studies to further evaluate the safety and efficacy of live, attenuated intranasal vaccine candidates targeting a combination of PIV3 and RSV or PIV3 and hMPV. Should additional preclinical studies continue to show promising results, MedImmune anticipates beginning human studies sometime in 2004.

Peter A. Kiener, D.Phil., MedImmune's vice president of research, added, "As evidenced by the success of Synagis(R) (palivizumab) and the recent approval of FluMist, MedImmune is a leader in the development, manufacture and commercialization of novel products to prevent respiratory infectious diseases. We plan to apply the expertise and insight gained in the development of these state-of-the-art products to our current development projects with the hopes that we will continue to reduce the impact of serious respiratory illnesses. Preventing serious respiratory infections caused by RSV, PIV3 and hMPV would have a significant, positive impact on public health."

FluMist is the first advance in flu vaccine technology in more than 50 years. It uses nasally administered, live, attenuated, cold-adapted, virus technology to stimulate both an antibody response in the bloodstream (systemic immunity), as well as an immune response in the nasal passage (mucosal/local immunity) -- the usual point of entry for airborne respiratory viruses. The U.S. Food and Drug Administration (FDA) approved FluMist in June 2003. Synagis, approved in 1998, is the first and only monoclonal antibody approved for an infectious disease. To date, Synagis has been used to help prevent serious lower respiratory tract disease caused by RSV in approximately 500,000 pediatric patients at high risk of RSV disease worldwide.

RSV, hMPV and human PIV3 are serious viruses that cause respiratory disease, particularly in young children, the elderly, and immunocompromised individuals. RSV is the most common cause of lower tract respiratory infections in infants and children worldwide, typically occurring during the fall and winter months. A recently identified virus, hMPV is believed to cause serious lower respiratory tract infections in young children. PIV3 is the leading cause of croup, an acute lower respiratory disease most often observed in young children.

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, as well as copies of the product inserts for each product, 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.
    -0-                             09/30/2003
    /CONTACT:  Media: Jamie Lacey, +1-240-632-4035; or Investors: Will
Roberts, +1-301-527-4358, or John Filler, +1-240-632-4086, all of MedImmune,
Inc./
    /Web site:  http://www.medimmune.com/
    (MEDI)

CO:  MedImmune, Inc.
ST:  Maryland
IN:  MTC HEA PUB
SU:  SVY CHI



JV-TW 
-- DCTU028 --
2651 09/30/2003 10:38 EDT http://www.prnewswire.com