Glaxo starts human tests of bird flu vaccines
Date: 6.4.2006
WASHINGTON -- GlaxoSmithKline said yesterday it has started human trials of two new bird flu vaccines and that if the treatments work, they could be ready to manufacture by the end of the year.
The company believes its vaccines will work more efficiently than one made by rival Sanofi-Aventis, which US researchers said Wednesday worked well only at the highest doses and even then in only half the people immunized.
Glaxo believes its advantage lies in the adjuvants -- additives put into vaccines that boost the immune system and make it respond more efficiently.
If all goes well, the company could start making the vaccine at the end of the year, after the results of the trials, said David Stout, president of pharmaceutical operations at Glaxo.
''It is then a case of just mixing," Stout told reporters in a telephone briefing.
The virus is grown in eggs and then inactivated, and the adjuvant is simpler to make ''Then you just combine the two and shake it up," Stout said.
The Sanofi vaccine only produced a satisfactory immune response in volunteers at 12 times the dose needed for the annual seasonal flu shot.
Glaxo plans to test much lower doses of its vaccine in 800 volunteers in Germany and Belgium -- starting at one-quarter of the current dose.
The adjuvant tested in the 400 Belgian volunteers will be alum, already used in some vaccines, and the German trial will use a secret mixture of proprietary adjuvants the company has been working on, the Glaxo officials said.
Dr. Bruce Innis, a viral vaccine expert and vice president at Glaxo, said if the adjuvants work as expected, the vaccines might protect people from ''drifted" strains of H5N1 -- those that have evolved slightly and do not precisely match the strain of virus used in the vaccine.
''We think such a vaccine could offer a better option to governments with regard to stockpiling," Innis said.
The H5N1 strain of avian influenza has spread rapidly out of eastern Asia in recent months, causing outbreaks in India, infecting birds in western Europe, across parts of the Middle East, and down into West Africa.
It almost exclusively infects birds but has sickened 186 people in eight countries and has killed 105 of them. Experts believe it poses the greatest threat yet of a pandemic, a global epidemic of flu that could kill millions, if it acquires the ability to pass easily from human to human.
A key challenge in the race to develop a potential pandemic flu vaccine is how to make the maximum number of shots from the minimum amount of antigen -- the killed virus used to prep the immune system.
Governments are also urging companies to step up production capacity. Existing vaccine factories can make only 900 million doses of influenza vaccine globally -- far short of what would be needed in a pandemic when billions of people would need to be vaccinated.
Stout said Glaxo is gearing up for this, working on a new factory in Pennsylvania that will use cell cultures to make flu vaccines, instead of the current, old-fashioned and uncertain method in which the vaccine antigen virus is grown in eggs.
"Source":[ http://www.boston.com/business/globe/articles/2006/03/31/glaxo_starts_human_tests_of_bird_flu_vaccines/].
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