MedImmune's Motavizumab Reduced RSV Hospitalizations by 83 Percent Among High-Risk Native American, Full-Term Infants in Placebo-Controlled Phase 3 study

MedImmune's Motavizumab Reduced RSV Hospitalizations by 83 Percent Among High-Risk Native American, Full-Term Infants in Placebo-Controlled Phase 3 study

August 24, 2007

    GAITHERSBURG, Md., Aug. 24 /Xinhua-PRNewswire/ -- 

    MedImmune, Inc. today announced that in a Phase 3
study, motavizumab was shown to reduce hospitalizations due
to respiratory syncytial virus (RSV) by 83 percent as
compared to placebo (8.3 percent in placebo arm vs. 1.4
percent in motavizumab; p<0.001), as the trial's primary
endpoint. In addition, the trial showed a 71-percent
reduction in the incidence of RSV-specific lower
respiratory infections (LRIs) requiring outpatient
management (9.5 percent in placebo group and 2.8 percent in
the motavizumab group; p<0.001), which was a secondary
endpoint.

    Motavizumab is an investigational monoclonal antibody
(MAb) being evaluated for its potential to prevent serious
disease caused by RSV in high-risk pediatric patients. This
Phase 3 trial involved 1,410 full-term infants less than six
months of age in two Native American populations. In
previous medical studies these populations were shown to
have high rates of hospitalization due to RSV.

    The randomized (2:1), double-blind study was designed
to compare monthly intramuscular injections of motavizumab
against placebo. After an interim analysis conducted by an
independent data safety monitoring committee, the study was
unblinded early due to statistical evidence demonstrating
that motavizumab reduced RSV hospitalizations and LRIs
requiring outpatient medical management within this
population. Kate O'Brien, M.D., associate professor at the
Center for American Indian Health, Johns Hopkins Bloomberg
School of Public Health, served as the study's principal
investigator.  

    "We are pleased with the results of this study
which support the positive results seen in our Phase 3
pivotal trial comparing motavizumab and Synagis(R)
(palivizumab) that were previously reported at the
Pediatric Academic Societies meeting in May 2007,"
said Genevieve Losonsky, M.D., vice president, clinical
development, infectious disease, MedImmune. 

    Motavizumab was well tolerated in these Native American
infants, with an overall incidence and severity of adverse
events (AEs) that were similar between the motavizumab and
the placebo groups.  The mortality rates were not
statistically different between groups (0.4 percent in the
placebo arm, n=2 and 0.3 percent in the motavizumab arm,
n=3) and were not considered to be related to the study
drug. As was suggested in the pivotal Phase 3 trial
conducted in high-risk, preterm infants, rates of
hypersensitivity related skin rashes within two days of
dosing were seen in about one percent of treated children
in the motavizumab group.  

    MedImmune's Commitment to RSV Prevention

    MedImmune is a world leader in the development of
innovative therapeutic biologic products to prevent RSV
disease.  In 1996, MedImmune launched the first anti-RSV
drug, RespiGam(R) (respiratory syncytial virus immune
globulin intravenous (human) (RSV-IGIV)), which was a
polyclonal antibody administered via four-hour intravenous
infusion.  In 1998, MedImmune introduced Synagis, which was
a significant product improvement as a monthly intramuscular
injection for the prevention of severe RSV, as well as being
the first MAb to receive U.S. Food and Drug Administration
(FDA) approval for an infectious disease.  With the
development of motavizumab, MedImmune continues to
reinforce its commitment to developing anti-RSV products.
In a head-to-head comparative Phase 3 trial with Synagis,
motavizumab met its primary endpoint of reducing
RSV-related hospitalizations in high-risk pediatric
patients and met its secondary endpoint of reducing
medically attended, outpatient respiratory tract infections
in that patient group. MedImmune is also developing a
small-molecule product candidate to prevent RSV as well as
a vaccine against RSV, both of which are in Phase 1
clinical trials.

    About RSV 

    Each year, up to 125,000 infants in the U.S. are
hospitalized with severe RSV infections, the leading cause
of lower respiratory tract infections in infants in the
United States. RSV is the most common respiratory infection
in infancy or childhood. Approximately one-half of all
infants are infected with RSV during the first year of
life, and nearly all children have been infected at least
once by the time they reach their second birthday. Children
born prematurely as well as those with chronic lung disease
(CLD) or congenital heart disease (CHD) are at highest risk
for severe disease and hospitalization due to RSV. The virus
may also cause severe illness in other high-risk groups such
as the elderly, those with underlying respiratory or cardiac
disease, and those with compromised immune systems (e.g.,
bone marrow transplant patients). 

    About Motavizumab 

    Motavizumab, formerly known as Numax(R), is an
investigational humanized MAb being evaluated for its
potential to prevent serious lower respiratory tract
disease caused by RSV in pediatric patients at high risk of
RSV disease. Phase 1 and Phase 2 study data have been
reported showing that motavizumab appears to have a similar
safety and pharmacokinetic profile to Synagis in infants.
Additionally, in early phase studies children treated with
motavizumab had reduced RSV replication in the upper
respiratory tract.  In its first pivotal trial, which was a
head-to-head comparative trial with Synagis, motavizumab
demonstrated a 26-percent reduction in RSV hospitalizations
due to RSV and a 50-percent reduction in the incidence of
RSV lower respiratory tract infections requiring outpatient
management, its secondary endpoint.       

    About Synagis 

    Synagis is the only monoclonal antibody approved by the
FDA to help prevent an infectious disease. Synagis was
approved for use in the United States in 1998, Europe in
1999, and Japan in 2002.  Synagis is currently available in
62 countries.  

    Synagis is indicated for the prevention of serious
lower respiratory tract disease caused by respiratory
syncytial virus (RSV) in pediatric patients at high risk of
RSV disease and is administered by intramuscular injection.
The safety and efficacy of Synagis were established in
infants with bronchopulmonary dysplasia (BPD), infants with
a history of prematurity (less than or equal to 35 weeks
gestational age), and children with hemodynamically
significant congenital heart disease.  The first dose of
Synagis should be administered prior to commencement of the
RSV season, which usually starts in the fall and runs
through the spring. Patients, including those who develop
an RSV infection, should continue to receive monthly doses
throughout the season.

    Very rare cases (<1 per 100,000 patients) of
anaphylaxis and rare (<1 per 1,000 patients)
hypersensitivity reactions have been reported with Synagis.
Cases of anaphylaxis were reported following re-exposure to
Synagis and rare severe hypersensitivity reactions occurred
on initial exposure or re-exposure. If a severe
hypersensitivity reaction occurs, therapy with Synagis
should be permanently discontinued. If milder
hypersensitivity reaction occurs, caution should be used on
re-administration of Synagis. 

    In clinical trials, the most common adverse events
occurring at least one percent more frequently in
Synagis-treated patients than controls were upper
respiratory infection, otitis media, fever and rhinitis.
Cyanosis and arrhythmia were seen in children with CHD. 

    The pivotal trial for Synagis was called the IMpact
trial and comprised a total of 1,502 children who were
randomized (500 placebo, 1,002 Synagis) in a double-blind,
placebo-controlled protocol where 1,486 children completed
the study's follow-up.

    In the IMpact trial, monthly prophylaxis with Synagis
via intramuscular injections was associated with a
55-percent reduction in hospitalization as a result of RSV
(p=<0.001). Reductions were observed in both children
with bronchopulmonary dysplasia (38 percent reduction) and
premature children without BPD (78 percent reduction).
Approximately 50 percent of the children in the analysis
had BPD. 

    For full prescribing information for Synagis, see the
company's website at:
http://www.medimmune.com/products/synagis/index.asp . 

    About International RSV Prophylaxis

    Outside the United States, Synagis is distributed by
Illinois-based Abbott, a global, broad-based health care
company.  Abbott also has the ex-U.S. distribution rights
to motavizumab.

    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 diseases, cancer and
inflammatory diseases.  With approximately 3,000 employees
worldwide and headquarters in Maryland, MedImmune is wholly
owned by AstraZeneca plc (LSE: AZN.L, NYSE: AZN). For more
information, visit MedImmune's website at
http://www.medimmune.com .


    For more information, please contact:

    Media - 
     Tor Constantino
     MedImmune, Inc.
     Tel:  [phone]

    Investors - 
     Peter Vozzo
     MedImmune, Inc.
     Tel:  [phone]