China to start 2nd trial for bird flu vaccine
(Reuters)
Updated: 2006-10-12 16:36
A Chinese company that is developing a H5N1 bird flu vaccine for humans plans
to kick off a second clinical trial before the end of the year and will have its
production capacity expanded ten-fold by mid-2007.
"The second clinical
trial should be over by July or August next year, just before the flu season
begins," Yin Weidong, managing director of state-backed Beijing Sinovac Biotech
Co., told Reuters in an interview on Thursday.
He tried to ease concerns
over using a strain of the virus found in Vietnam in the vaccine, saying it
would offer some protection against other H5N1 strains.
The company
needs to obtain the approval of the State Food and Drug Administration (SFDA)
for the second trial and will file its application with the agency within the
next two weeks.
"The government values this project very highly and it
will get going faster," Yin said. He added that the World Health Organisation
had provided advice in the first clinical trial and would probably do so again
in the second trial.
Sinovac ran its first clinical trial involving 120
volunteers in Beijing this year.
It published its findings in The Lancet
medical journal in September, saying the experimental vaccine was effective and
well tolerated at low doses.
It used whole-virus vaccine in 1.25, 2.5, 5
and 10 microgram amounts, but the 10 microgram dose was found to be most
effective in producing an immune response.
The volunteers, aged between
18 and 60, did not suffer serious side effects, but some experienced pain,
swelling and fever.
The second trial will have a wider age limit, taking
in people below 18 and over 60, but Yin said the drug administration would make
the final decision.
Apart from Beijing, Sinovac will look for volunteers
in two other cities, most likely in southern China. There will be two dosages: 5
and 10 micrograms.
By mid-2007, Sinovac will have expanded its
production capacity to 20 million doses from a current 2 million, but when the
vaccine goes into production will hinge on how soon it secures orders.
Sinovac and several companies around the world are in a race to develop
a vaccine to combat what experts fear would be a flu pandemic triggered by the
H5N1 bird flu virus, which has killed 148 people since late 2003.
Although it remains a disease among birds, scientists say it could wreak
havoc and kill millions if it mutates and learns to transmit efficiently among
humans.
Some experts, however, question the rationale behind designing
these "pre-pandemic vaccines" based on a H5N1 strain found in Vietnam in recent
years, saying they might not protect against other H5N1 strains and the eventual
pandemic strain.
At least two other H5N1 strains have become
geographically more widespread; with one spreading across not only Asia, but
parts of Europe, Africa and the Middle East.
But Yin said there should be
some amount of cross protection.
"Even though the virus is changing, it
is still H5N1. We are facing one enemy," he said.
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