Bird Flu: Science and Policy

[DewDiligence]

GSK’s Vaccine Provides Cross-Immunity

http://online.wsj.com

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LONDON March 5 (Dow Jones)--GlaxoSmithKline PLC's (GSK) pre-pandemic flu vaccine can protect against diverse strains of H5N1, the virus involved in recent outbreaks of bird flu, the company said Monday.

According to the results of two new studies, the experimental vaccine provides a significant level of cross-immunity, since it can recognize and kill a strain that differs from the one used in its formulation.

"This means that proactive administration of our pre-pandemic vaccine before or just after the start of the pandemic could help to substantially slow down the spread of disease," said Jean Stephenne, President of GlaxoSmithKline Biologicals, the drugmaker's vaccine unit.

In the first study, which tested 400 adults, the vaccine stimulated a strong immune response against the Indonesian strain of the virus, even with low levels of antigen - the substance that stimulates an immune response.

The results were achieved thanks to GlaxoSmithKline's own adjuvant system, or booster, which requires a significantly lower amount of antigen to raise a strong immune response. This could give the ability to produce very large quantities of the product for mass vaccination, according to the company.

The second study, carried out on ferrets, showed that the vaccine could protect against two different H5N1 flu strains, also at very low levels of antigen.

"Cross-immunity is certainly being driven by the adjuvant," said Rip Ballou, GlaxoSmithKline's vice president of clinical research and development, adding that rival experimental vaccines have shown limited cross-protection data.

Both Sanofi-Aventis SA (SNY) and Novartis AG (NVS) are developing pandemic vaccines.

GlaxoSmithKline's pre-pandemic vaccine has already been accepted for review by the European health regulator in January. However the company doesn't yet have a planned date for a marketing application in the U.S., Ballou said.

The pre-pandemic vaccine could be adapted for pandemic use once the virus responsible for any flu pandemic has been identified.

The E.U. regulator has already endorsed GlaxoSmithKline's mockup pandemic vaccine, Daronrix.

The European Medicines Agency's mockup application allows vaccine manufacturers to go through many of the stages of regulatory approval on the basis of one virus strain.

Once any actual pandemic strain has been identified, drug companies would then simply replace the mockup strain without having to go through the entire regulatory process from scratch.

The strain which GlaxoSmithKline used to develop Daronrix is derived from the H5N1 strain.
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