Glaxo starts trials of H5N1 pandemic flu vaccine

LONDON, Mar 30: GlaxoSmithKline Plc said today it had started clinical trials of two pandemic vaccines against the H5N1 strain of bird flu in humans and reiterated plans to have a shot in production by the year end.

One trial in Germany is testing a flu vaccine made with a classic adjuvant, or additive, while the second study in Belgium involves a novel adjuvant, which Glaxo believes could help stretch supplies of vaccine in the event of a pandemic.

A total of 800 healthy volunteers have been enrolled in the two trials.

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, or active ingredient.

''The second vaccine may offer governments a preferred option to proactively stockpile and begin vaccination before the onset of a pandemic, significantly increasing the speed of a public health response in the event of an outbreak,'' Glaxo head of vaccines Jean Stephenne said.

The British-based company has already submitted a ''mock-up'' dossier to European healthcare regulators seeking outline clearance to market a vaccine against pandemic flu, the first manufacturer to do so under new EU rules designed to fast-track approval.

Should a pandemic flu strain emerge, a variation to the dossier would allow rapid European registration and production.

Experts fear the H5N1 strain of virus now circulating in birds will mutate enough to allow it to pass easily from person to person.

If it does, it could cause a catastrophic pandemic, killing tens of millions of people, because humans lack immunity to it.

No one knows how well human H5N1 vaccines will match a future pandemic strain but they might ''prime'' a person's immune system.

''We believe that vaccinating populations with the appropriate H5N1 vaccine will help educate the body's immune system and reduce expected morbidity and mortality associated with a pandemic,'' Glaxo flu operations head Emmanuel Hanon said.

''This means that if the current bird flu virus mutates to allow human-to-human transmission, a vaccinated person will be better prepared to combat the H5N1 pandemic flu virus.'' Glaxo is one of several companies, including Sanofi-Aventis SA and Chiron Corp, working to develop a vaccine against the H5N1 strain of virus.

The normal seasonal flu vaccine provides no protection against pandemic disease.

REUTERS