VACCINES

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Because Phase III trials are complex and costly, researchers
have introduced the intermediary Phase IIb trial. A Phase
IIb trial provides preliminary information about how
well the vaccine will work and helps researchers decide
whether to move it into a Phase III trial. Phase IIb trials
enroll more volunteers than a Phase II trial but fewer
than a Phase III trial. A candidate vaccine that tests well
in a Phase IIb trial would still need to be tested in a
Phase III trial.
Scientists cannot, of course, deliberately expose human
volunteers to certain microbes, such as Ebola or anthrax,
to determine how well a vaccine works. So, FDA has a
rule that in developing vaccines against certain microbes,
scientists can gather efficacy information through animal
rather than human tests.
FDA License
The application to FDA for a license to market a vaccine
is called a Biologics License Application (BLA). This
application must provide the results of all relevant
human studies, describe all manufacturing and testing
methods, and show the results of safety and purity tests
on batches of the vaccine intended for public use. A BLA
must also demonstrate that the vaccine manufacturers
comply with all government standards, including those
for production facilities, personnel, equipment, packaging,
and record-keeping. At this stage, FDA also inspects the
manufacturing facility.
The BLA is reviewed first by a team of FDA experts,
then by an advisory committee made up of scientists,
physicians, statisticians, and consumer representatives.
The committee votes on whether or not to recommend
that FDA approve the vaccine.