Data From 2004-2005 Flu Season Support Prior Findings of CAIV-T Effectiveness Across Influenza StrainsTORONTO, Oct 13, 2006 /PRNewswire-FirstCall via COMTEX News Network/ -- MedImmune, Inc. (Nasdaq: MEDI)
today announced results of a study that demonstrated higher influenza serum
antibody responses in children receiving its next-generation, investigational
intranasal influenza vaccine, CAIV-T (cold adapted influenza vaccine,
trivalent), than in children who received the traditional injectable trivalent
inactivated flu vaccine (TIV). In this study involving 52 children between
six and 35 months of age, CAIV-T prompted significantly higher seroconversion
rates and higher antibody titers than TIV. CAIV-T also demonstrated
significantly more cross-reactivity to the mismatched strain that
predominantly circulated during the 2004-2005 season. The results were
presented here today at the 44th Annual Meeting of the Infectious Diseases
Society of America (IDSA).
"These data are consistent with the results from our Phase 3 study
conducted during the 2004-2005 season that demonstrated CAIV-T's increased
efficacy against matched and mismatched strains in children under five years
of age compared to TIV," said Robert Belshe, M.D., director of the Center for
Vaccine Development at Saint Louis University School of Medicine.
In the study titled Immunogenicity of Cold-Adapted Influenza Vaccine,
Trivalent (CAIV-T) Compared with Trivalent Inactivated Influenza Vaccine (TIV)
in Children 6-35 Months of Age, a group of influenza-vaccine-naive children
(randomized 1:1) received two doses of CAIV-T or TIV approximately 35 days
apart. The children's immune responses (measured by serum hemagglutination
inhibition [HAI] antibody levels) were evaluated at the time of enrollment,
just prior to and approximately 30 days after the second dose. Study results
indicated that CAIV-T produced significantly higher antibody responses than
TIV against vaccine-like virus strains (matched) as well as against mismatched
viruses that were circulating during the 2004-2005 season in seronegative
children. Higher antibody responses were seen for CAIV-T after both the first
and second doses.
Strain-specific Seroconversion Rates in Seronegative Children
Post dose 1 CAIV-T vs. TIV Post dose 2 CAIV-T vs. TIV
Matched A/H1N1 Matched A/H1N1
53% vs. 0%* 94% vs. 8%*
Matched A/H3N2 Matched A/H3N2
100% vs. 29%* 100% vs. 100%
Mismatched A/H3N2 Mismatched A/H3N2
93% vs. 0%* 93% vs. 14%*
Matched B Matched B
67% vs. 17% 78% vs. 57%
Mismatched B Mismatched B
50% vs. 13% 100% vs. 60%*
*Significant difference between CAIV-T and TIV
Regulatory Status of CAIV-T
The U.S. Food and Drug Administration (FDA) is currently reviewing a
supplemental biologics licensing application (sBLA) submitted by MedImmune to
switch formulations from frozen FluMist(R) (Influenza Virus Vaccine Live,
Intranasal), currently approved in healthy individuals 5 to 49 years of age,
to the refrigerator-stable CAIV-T formulation, for the same population.
MedImmune has also submitted a separate sBLA to the FDA seeking an expanded
label for CAIV-T for use in children between 12 months and 59 months of age
who do not have a history of wheezing or asthma. A response from the FDA for
this sBLA is anticipated in the second quarter of 2007 and pending positive
outcome, MedImmune plans to commercially provide CAIV-T for the 2007-2008
influenza season.
About CAIV-T
CAIV-T is an investigational intranasal, cold-adapted trivalent influenza
vaccine. It is the refrigerator-stable formulation of FluMist, which is a
frozen, live attenuated cold-adapted trivalent influenza vaccine. To date, the
safety, tolerability and efficacy of CAIV-T has been studied in both healthy
and at-risk populations between the ages of 6 weeks and 98 years.
On May 1, 2006 at the Pediatric Academic Societies' annual meeting,
MedImmune presented its pivotal Phase 3 study for CAIV-T, entitled,
"Comparison of the Efficacy and Safety of Cold-Adapted Influenza Vaccine,
Trivalent with Trivalent Inactivated Influenza Vaccine in Young Children 6 to
59 Months of Age." The study included 8,475 children at 249 sites in 16
countries in North America, Europe, the Middle East and Asia. Study
participants were randomized one-to-one to receive either CAIV-T or the flu
shot during the 2004-2005 influenza season. Each participant also received a
placebo nasal spray or placebo injection to preserve the double-blind design
of the study. Participants were followed through the influenza season and
evaluated to identify illnesses caused by influenza virus. The trial included
more than 6,300 previously unvaccinated children and nearly 50 percent of the
children enrolled were less than 2 years of age.
The results of this trial showed that CAIV-T was 55 percent more effective
than the trivalent injectable inactivated influenza vaccine (TIV) in reducing
influenza illness caused by any influenza strain in children 6 months to 59
months of age, including both matched and mismatched strains. The influenza
attack rate was 8.6 percent for study participants receiving the flu shot
compared to 3.9 percent for those who received CAIV-T (P<0.001). Against
matched strains alone, CAIV-T was 45 percent more effective than the flu shot
(attack rates: TIV = 2.4 percent, CAIV-T = 1.4 percent; P<0.001). In this
study, CAIV-T was also shown to be 89 percent more effective than the flu shot
in reducing influenza illness caused by the matched H1N1 A strain (attack
rates: TIV = 0.7 percent, CAIV-T = 0.1 percent; P<0.001) and 79 percent more
effective than the flu shot against the circulating mismatched H3N2 A strain
(attack rates: TIV = 4.5 percent, CAIV-T = 0.9 percent; P<0.001). There were
no cultures of mismatched H1N1 strains or matched H3N2 strains detected in the
trial. While there were 16-percent fewer children with illnesses associated
with B strains in the CAIV-T group compared to TIV (attack rates: TIV= 3.5
percent, CAIV-T = 2.9 percent), this difference was not statistically
significant.
In the study, the overall incidence of adverse events and serious adverse
events was similar in both groups except for a higher incidence of runny nose
and nasal congestion in CAIV-T recipients (4.4 - 11.1 percent increase) and a
higher incidence of injection site reactions in those receiving the flu shot
(3.6 - 7.6 percent increase). A statistically significant increase in the
incidence of medically significant wheezing was seen in CAIV-T recipients 6
months to 23 months of age within 42 days following vaccination. Post-hoc
analyses showed higher all-cause hospitalizations occurring through 180 days
after vaccination in CAIV-T recipients 6 months to 11 months of age. Risk-
benefit analyses showed a favorable profile for CAIV-T as compared to TIV in
children 12 months to 59 months of age without a prior history of wheezing or
asthma.
About FluMist
FluMist is indicated for active immunization for the prevention of disease
caused by influenza A and B viruses in healthy children and adolescents, 5 to
17 years of age, and healthy adults, 18 to 49 years of age. There are risks
associated with all vaccines, including FluMist. Like any vaccine, FluMist
does not protect 100 percent of individuals vaccinated. In studies of people
between the ages of 5 and 49 years, runny nose was the most commonly reported
side effect. Other common side effects included various cold-like symptoms,
such as headache, cough, sore throat, tiredness/weakness, irritability, and
muscle aches.
FluMist should not be used, under any circumstances, in anyone with an
allergy to any part of the vaccine, including eggs; in children and
adolescents receiving aspirin therapy; in people who have a history of
Guillain-Barre syndrome; and in people with known or suspected immune system
problems. Pregnant women and people with certain medical conditions, asthma,
or reactive airways disease should not get FluMist.
Please see the Prescribing Information at
http://www.flumist.com/pdf/prescribinginfo.pdf, visit http://www.flumist.com,
or call 1-877-633-4411 for additional information.
About MedImmune
MedImmune strives to provide better medicines to patients, new medical
options for physicians, rewarding careers to employees, and increased value to
shareholders. 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 more than 2,400 employees worldwide,
MedImmune is headquartered in Maryland. For more information, visit the
company's website at http://www.medimmune.com.
This announcement contains, in addition to historical information, certain
"forward-looking statements" relating to CAIV-T and FluMist. Such forward-
looking statements are based on current expectations and involve inherent
risks and uncertainties, including factors that could delay, divert or change
current expectations and could cause actual outcomes and results to differ
materially from current expectations. In addition to risks and uncertainties
discussed in MedImmune's filings with the U.S. Securities and Exchange
Commission, no assurance exists that development efforts for CAIV-T will
succeed, that CAIV-T will receive required regulatory approval or that, even
if regulatory approval is received, CAIV-T will be commercially successful.
MedImmune undertakes no obligation to update any forward-looking statement,
whether as a result of new information, future events or otherwise except as
may be required by applicable law or regulation.
SOURCE MedImmune, Inc.
Media: Karen Lancaster, +1-301-398-5864, or Jamie Lacey, +1-301-398-4035, or
Investors: Peter Vozzo, +1-301-398-4358, all of MedImmune, Inc.
http://www.medimmune.com