Pandemic (H1N1) 2009 Influenza Update: Results from second clinical trial of GSK’s H1N1 adjuvanted vaccine confirm immune response and tolerability

Issued:     Friday 16 October 2009, London, UK

GlaxoSmithKline (GSK) today announced results from a second clinical trial of its pandemic (H1N1) adjuvanted vaccine, which demonstrate that one dose of the vaccine can provide a strong immune response which exceeds criteria as defined by international licensing authorities using the lowest dose of antigen available in pandemic vaccines.  The data from GSK’s H1N1 trials announced to date demonstrate the vaccine is generally well tolerated. The vaccine in this trial contains 3.75 µg of H1N1 antigen, which is the EMEA approved final formulation.

The trial, which is taking place in Belgium, involves 130 healthy volunteers aged 18 to 60 years old, and has been designed to evaluate the tolerability and immunogenicity of GSK’s split-virus pandemic (H1N1) adjuvanted vaccine in comparison with an unadjuvanted study formulation.

In 100% of the subjects receiving the adjuvanted vaccine the resulting hemagglutination-inhibition titres exceeded the regulatory threshold of 1:40 seroprotection after the first dose.  In the subjects in the unadjuvanted group, 93% reached the same threshold. These results were obtained 3 weeks following vaccination.

To date 2,000 people have received GSK’s H1N1 vaccine in clinical trials. Initial results for the first 356 subjects have demonstrated that the H1N1 adjuvanted vaccine has a similar tolerability profile to the previously EMEA approved H5N1 adjuvanted vaccine.  The adjuvant system in GSK’s influenza vaccine has already been tested in more than 41,000 people in GSK’s influenza programmes including the H5N1, the H1N1 and the adjuvanted seasonal flu vaccine and candidate vaccines. Further results on the H1N1 clinical trials will follow as the data become available.

GSK’s H1N1 flu pandemic vaccine Pandemrix™ was approved for use in 27 European countries on 30^th of September by the European Medicines Evaluation Agency.

GSK has delivered first supplies of over 7 million doses during the first week of shipments. Deliveries are continuing and GSK anticipates increasing the amount being shipped to governments in the coming weeks as additional manufacturing regulatory approvals are received.

Further information on GSK’s development of a vaccine to protect against pandemic (H1N1) 2009, including explanation of the vaccine development process and background information on adjuvants is available on: www.gsk.com/media/pandemic-flu.htm

GlaxoSmithKline – one of the world’s leading research-based pharmaceutical and healthcare companies – is committed to improving the quality of human life by enabling people to do more, feel better and live longer.  For further information please visit www.gsk.com

Cautionary statement regarding forward-looking statements
Under the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995, GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Factors that may affect GSK' s operations are described under 'Risk Factors' in the 'Business Review' in the company' s Annual Report on Form 20-F for 2008.