GlaxoSmithKline European regulatory update on Pandemrix™

Issued: London UK

GlaxoSmithKline (GSK) announced today that the European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) has recommended an update to the product label for the H1N1 influenza vaccine, Pandemrix.

Based on a review of currently available information on an increased number of reported cases of narcolepsy among children and adolescents in a small number of European countries, the CHMP confirmed that the overall benefit-risk balance for Pandemrix remains positive.

The CHMP recommended that the product information for Pandemrix should be updated to state that in persons under 20 years of age, Pandemrix should only be used if the recommended seasonal trivalent influenza vaccine is not available, and if immunisation against H1N1 is still needed, for example, in persons at risk of the complications of infection. This revision does not apply to adults over 20 years of age.

The label revision concludes an ongoing review of data by the CHMP, including the preliminary findings of an epidemiological study of narcolepsy and pandemic vaccines across a network of research and public health institutions (VAESCO) in eight European countries, as well as epidemiological data from Finland and Sweden. The preliminary findings of the VAESCO study confirmed a signal in Finland, but do not enable conclusions to be drawn in other countries, where vaccination coverage with Pandemrix was lower. Epidemiological studies in Finland and Sweden suggest an association between Pandemrix vaccination and narcolepsy in children and adolescents in those countries. The CHMP stated that further research is necessary in order to determine the potential role of genetic, environmental and other factors in raising the risk of narcolepsy.

This label update supersedes advice to healthcare professionals introduced in April this year recommending they perform an individual benefit-risk assessment, taking the narcolepsy information into account when considering the use of Pandemrix in children and adolescents.

GSK is committed to patient safety and will continue to work closely with the EMA and other national regulatory organisations in the best interest of patients. Further information from ongoing studies, including the final data from the VAESCO study and an epidemiological study in Canada being supported by GSK, is however still needed in order to gain additional insight into the cause of the reported cases of narcolepsy. In addition, GSK has committed to conduct further research into any potential association between Pandemrix and narcolepsy and will seek independent expert advice on this research activity, as agreed with the EMA.

Over 31 million doses of Pandemrix have been administered worldwide in 47 countries. A total of 335 cases of narcolepsy in people vaccinated with Pandemrix have been reported to GSK as of 6 July 2011, with 68% of these cases of narcolepsy originating from Finland and Sweden.

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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 2010.