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原帖由论坛会员aivr145发表于 2009-2-26 20:50
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Clinical data from a Phase III and subsequent booster study demonstrate safety,
immune response and cross-protective memory
DEERFIELD, Ill.--(Business Wire)--
Baxter International Inc. (NYSE: BAX) today announced that the Committee for
Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMEA)
has issued a positive opinion for the marketing authorization of CELVAPAN, the
first cell culture-based H5N1 (avian flu) pandemic vaccine, in the European
Union.
The positive opinion precedes the licensure of themock-upvaccine, which
allows CELVAPAN to be used if the World Health Organization (WHO) officially
declares a pandemic. The positive opinion was based on results from a
comprehensive clinical development program, including a Phase III clinical trial
that demonstrated vaccines for two different H5N1 virus strains were well
tolerated and generated a functional immune response.
We are very pleased to receive the EMEA s positive opinion for CELVAPAN,said
Hartmut Ehrlich, M.D., vice president, BioScience global research and
development.This is another step towards our goal of supplying a safe and
effective vaccine to protect the population against a possible influenza
pandemic.
Amock upvaccine is identical to the future pandemic vaccine in composition
and manufacturing; however, since the actual pandemic strain is not known, the
vaccine contains another influenza strain not yet exposed to the general
population. Once a pandemic is declared, this licensure allows for a fast track
approval of the vaccine containing the actual pandemic strain.
CELVAPAN is made using Baxter s proprietary Vero cell technology, which offers
advantages against conventional egg-based vaccine technology. Baxter s Vero cell
manufacturing process is more rapid due to its ability to use thenativevirus
that does not need to be modified in order to grow in chicken eggs. The shorter
time for vaccine production is critical in accelerating vaccine supply in
response to an influenza pandemic.
CELVAPAN is produced in Bohumil, Czech Republic, at one of the largest cell
culture vaccine production facilities in the world. Vero cell technology uses a
well-established continuous mammalian cell line to produce the pandemic vaccine.
Baxter s candidate avian flu vaccine is derived from the H5N1 strain
A/Vietnam/1203/2004. Its antigen composition and structure are identical to the
actual virus circulating in nature. This vaccine formulation alleviates the need
to enhance the immune response by including adjuvants (additives) that may cause
side effects. In the Phase III study, CELVAPAN induced an immune response that
is similar to the body s defense against a natural influenza virus infection.
Phase III Clinical Trial Results
The purpose of the randomized Phase III study was to evaluate safety and immune
responses to 7.5g of the Vietnam strain vaccine in two age groups (adults
18-59 and elderly, i.e., older than 60). The antibody persistence and immune
response to a booster with either the same or a different strain was also
measured. The study also investigated the ability of the vaccine to induce
cross-immunity against divergent H5N1 strains.
Overall, the vaccine was well tolerated after the first and second vaccination
as well as after the booster, with a safety profile similar to currently
licensed seasonal influenza vaccines. The most common side effects were
injection site pain and headache, fatigue or malaise.
A positive immune response was induced even after only one immunization as
determined by measurement of functional antibodies using a microneutralization
assay (50.7 percent in the adult group; 54.4 percent in the elderly group).
Following the second immunization, 73 percent of subjects in the adult and 74
percent in the elderly age group demonstrated seroneutralizing levels of
antibody, meaning the vaccine was found to be at least equally immunogenic in
the elderly as in the adult age group. A six-month booster vaccination with
either A/Vietnam/1203/2004 or A/Indonesia/05/2005 strain vaccines induced a
substantial booster response. A booster vaccination using a different strain
resulted in high levels of antibodies against the initial and the booster
strain, which is indicative of cross-protective immunological memory.
Last June, The New England Journal of Medicine published data demonstrating
CELVAPAN met Phase I/II trial endpoints for safety and immunogenicity
(generating a functional immune response). This was the first peer-reviewed
publication of study results for CELVAPAN, the first cell culture-derived avian
influenza vaccine to undergo clinical evaluation.
About Pandemic Flu
A pandemic is a global disease outbreak caused by an agent for which there is
little or no immunity in the human population and which can spread easily from
person-to-person worldwide causing serious illness and death. Most cases of
avian flu infection in humans have so far resulted from direct or close contact
with infected poultry (e.g., domesticated chicken, ducks, and turkeys) or
surfaces possibly contaminated from feces of infected birds. Avian influenza
infection follows an unusually aggressive clinical course, with rapid
deterioration and a high fatality rate.
About Baxter
Baxter International Inc. develops, manufactures and markets products that save
and sustain the lives of people with hemophilia, immune disorders, infectious
diseases, kidney disease, trauma, and other chronic and acute medical
conditions. As a global, diversified healthcare company, Baxter applies a unique
combination of expertise in medical devices, pharmaceuticals and biotechnology
to create products that advance patient care worldwide.
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