GlaxoSmithKline (GSK) has started an international clinical trial programme to test two pandemic vaccines against the H5N1 strain of the avian influenza virus in humans, GlaxoSmithKline Biologicals said in a press statement.

In one trial just initiated in 400 healthy adult volunteers in Germany is testing a pandemic flu vaccine using a classic alum adjuvant to improve individuals’ immune response and possibly allow a lower amount of antigen to be used per dose. This trial supports a dossier GSK submitted to European regulators in December 2005. Should a pandemic flu strain be identified by the World Health Organisation, a variation to the dossier would allow rapid European registration and production of a pandemic vaccine.

Parallelly, a clinical trial conducted in Belgium in 400 healthy adults is testing a candidate pandemic flu vaccine that contains a novel adjuvant system. GSK is hopeful that a vaccine formulated with this novel adjuvant will further enable individuals’ immune system to respond to different H5N1 virus strains, offering a broader protection against the threat of a pandemic.

GSK novel adjuvant technology is also expected to further reduce the amount of antigen needed per dose, increasing the number of doses the company could make available worldwide. Such a vaccine would offer governments additional options of stockpiling and vaccinating ahead of a pandemic
outbreak.

Both trials are testing the vaccine’s safety and ability to boost individuals’ immune response against H5N1. Tested vaccines are made from inactivated (killed) H5N1 virus. Different dose levels are being studied. Volunteers are to receive two vaccinations approximately three weeks apart.

The studies will allow GSK to select an optimal dose and formulation for subsequent safety trials in groups at high risk of complications following influenza infection, such as children and the elderly.

Preliminary results from the clinical trials are expected in the third quarter of 2006. GSK plans to have a pandemic flu vaccine in production before the
end of the year.