Interim Clinical Trial Results Show MedImmune's H1N1 Vaccine Has Similar Safety Profile as Seasonal Vaccine in Eligible Children and Adults

Interim Clinical Trial Results Show MedImmune's H1N1 Vaccine Has Similar
Safety Profile as Seasonal Vaccine in Eligible Children and Adults
H1N1 Immunogenicity Profile Also Consistent with Seasonal Vaccine Formulations

GAITHERSBURG, Md., Oct. 22 /PRNewswire/ -- MedImmune announced today that
interim data from human studies of its nasal spray vaccine for the 2009 novel
Influenza A (H1N1) virus demonstrate a similar clinical profile in children
and adults 2 to 49 years of age as previously studied seasonal formulations of
the vaccine. The live attenuated influenza vaccine (LAIV) for the 2009 novel
Influenza A (H1N1) virus received approval from the U.S. Food and Drug
Administration (FDA) on September 15, 2009.

"MedImmune is pleased to report these findings that demonstrate that the
safety profile and immunogenicity of our nasal spray vaccine for the 2009 H1N1
virus is, as expected, similar to our seasonal influenza vaccine," said Filip
Dubovsky, M.D., vice president, clinical development, vaccines. "It is
rewarding for all of us at MedImmune to see the vaccine being used to help
protect the U.S. population from this novel strain of influenza."

Two randomized, double-blind, placebo-controlled trials are ongoing in
children (2-17 years) and adults (18-49 years) to evaluate the safety,
tolerability, and immunogenicity of vaccine. A total of 326 children and 300
adults were randomly assigned to receive 2 doses of 2009 H1N1 LAIV or placebo
28 days apart. Both clinical trials are collecting data following a second
dose of the vaccine.

LAIV for 2009 H1N1 is made using the same process as LAIV for seasonal
influenza. The safety of the 2009 H1N1 vaccine was evaluated in the same way
that the safety of new seasonal LAIV strains is assessed every year. The H1N1
vaccine was also evaluated in children to further establish its safety
profile.

In children, the most common side effects following the first dose of vaccine
included headache, runny/stuffy nose, and cough. In adults, the most common
side effects were headache, runny nose and decreased activity. Symptoms after
the second dose were similar but generally occurred at lower rates in both
children and adults. No vaccine-related serious adverse events have been
reported in children or adults. The local and systemic symptoms observed are
consistent with intranasal vaccine virus replication and are similar to those
observed with seasonal LAIV. Serum antibody responses to the vaccine in
addition to pre-clinical characterization data are also consistent with
previously studied formulations of seasonal LAIV, which has been shown in
multiple studies to be safe and effective in eligible children and adults 2 to
49 years of age.

LAIV initiates the immune response in the nose, where the virus enters the
body and replicates, and is the key to establishing a vaccine response that
will help prevent disease if the person later encounters a circulating H1N1
virus. In response to the vaccine, the body develops mucosal immunoglobulin A
(IgA), serum immunoglobulin G (IgG), and cellular immunity to help protect the
individual from infection from an influenza virus.

Study results have been submitted to and reviewed by authorities at the FDA,
the U.S. Centers for Disease Control and Prevention (CDC), the National
Institutes of Health (NIH), and the U.S. Department of Health and Human
Services (HHS).

About LAIV
LAIV is different from the injectable influenza vaccine ("flu shot") in that
it contains live vaccine virus strains that are specifically designed to
prompt the body to begin mounting a protective response, but weakened so as
not to cause the flu. It is delivered into the nose, where the influenza
virus usually enters the body, rather than by injection. MedImmune's seasonal
influenza vaccine is currently licensed in the United States, South Korea, and
Hong Kong and MedImmune's H1N1 influenza vaccine is currently licensed in the
United States; both are approved for eligible individuals 2 through 49 years
of age.

Important Safety and Eligibility Information for Influenza A (H1N1) 2009
Monovalent Vaccine Live, Intranasal

Who may be eligible for Influenza A (H1N1) 2009 Monovalent Vaccine Live,
Intranasal?
Influenza A (H1N1) 2009 Monovalent Vaccine Live, Intranasal is a vaccine
approved for the prevention of influenza disease caused by pandemic (H1N1)
2009 virus in children, adolescents and adults, from 2-49 years of age.
Influenza A (H1N1) 2009 Monovalent Vaccine Live, Intranasal may not protect
everyone who gets it. This vaccine is for intranasal administration only.
Children 2 through 9 years of age are recommended to receive 2 doses of
vaccine approximately 1 month apart; individuals 10 years of age and older are
recommended to receive a single dose of vaccine.

Who may not be able to get Influenza A (H1N1) 2009 Monovalent Vaccine Live,
Intranasal?
Influenza A (H1N1) 2009 Monovalent Vaccine Live, Intranasal is not right for
everyone. This vaccine must not be given to: people with history of
hypersensitivity to eggs, egg proteins, gentamicin, gelatin or arginine;
people with life-threatening reactions to previous influenza vaccinations; and
children and adolescents receiving aspirin or aspirin-containing therapy.
Children less than 24 months of age are not eligible for this vaccine.

The following people may not be able to get Influenza A (H1N1) 2009 Monovalent
Vaccine Live, Intranasal or may be able to get it only in certain situations:
people with asthma or active wheezing, or children less than 5 years of age
with recurrent wheezing; people with a history of Guillain-Barre syndrome;
people with a weakened immune system; people with long-term medical conditions
including heart disease, kidney disease, and metabolic diseases, such as
diabetes; and pregnant women.

If a patient falls into one of these groups, a health care provider will
decide if Influenza A (H1N1) 2009 Monovalent Vaccine Live, Intranasal is right
for them.

For Complete Product Information please visit:
http://www.medimmune.com/pdf/products/h1n1_pi.pdf

About MedImmune
MedImmune, the worldwide biologics business for AstraZeneca PLC (LSE: AZN.L,
NYSE: AZN), has approximately 3,300 employees worldwide and is headquartered
in Gaithersburg, Maryland. With an advancing pipeline of promising candidates,
we aim to be the next revolutionary force in biotechnology by delivering
life-changing products, industry-leading performance, and a tireless
commitment to improving patient health. For more information, visit
MedImmune's website at www.medimmune.com.

The Novel Influenza A (H1N1) project has been funded in whole or in part with
the Federal funds from HHS/ASPR, under Contract No. HHSO100200900002I. The
opinions expressed herein do not represent opinions or statements made or
expressed by the U.S. Department of Health and Human Services.

SOURCE MedImmune

Karen Lancaster, +1-301-398-5864, lancasterk@medimmune.com or Tor Constantino,
+1-301-398-5801, constantinos@medimmune.com