GlaxoSmithKlineGlaxoSmithKline plc (LSE/NYSE: GSK) announced that the U.S. Food and Drug Administration (FDA) has approved its pandemic Influenza A (H5N1) Virus Monovalent Vaccine, Adjuvanted (also referred to as Q-Pan H5N1 influenza vaccine) for the immunisation of adults 18 and older for the prevention of disease caused by the influenza A virus H5N1 subtype contained in the vaccine. GSK received notification of the FDA approval late Friday afternoon (22 November).

The Q-Pan H5N1 influenza vaccine is composed of monovalent, inactivated, split A/H5N1 influenza virus antigen and GSK's AS03 adjuvant. In clinical studies, the adjuvanted formulation stimulated the required immune response while using a smaller amount of antigen as compared to a formulation without adjuvant. This could translate to a greater number of doses available at the time of a pandemic.

"Supporting the U.S. Government's capability to help protect Americans against pandemics ranks among GSK's most important U.S. public-health responsibilities," said Bruce Innis, Vice President of Vaccines Development for GSK. "H5N1-related illness has thus far been rare, but life-threatening when it has occurred. GSK scientists approached this clinical development project driven by the recognition that the resulting vaccine might be needed in the future to help protect millions of Americans against pandemic flu illness."

GSK will make this vaccine available in the U.S. only if directed to by the Biomedical Advanced Development and Research Authority (BARDA) in the U.S. Department of Health and Human Services' Office of the Assistant Secretary for Preparedness and Response. The GSK H5N1 pandemic influenza vaccine programme has been supported by a development contract (HHSO100200700029C) from BARDA.

Licensure of the Q-pan H5N1 influenza vaccine is supported by data generated in two pivotal clinical studies showing that the vaccine was immunogenic and generally well-tolerated. The efficacy of GSK’s seasonal influenza vaccine FluLaval® Quadrivalent in the prevention of influenza disease was also submitted as supportive information.

In clinical trials, the most common solicited local reactions and general adverse events were injection site pain and swelling, muscle aches, headache, fatigue, joint pain, shivering and sweating.

GSK's Influenza A (H5N1) Virus Monovalent Vaccine, Adjuvanted, has also received marketing authorisation in Europe and Canada under the brand names, Pumarix™ and Arepanrix™ H5N1, respectively.

More about the H5N1 influenza strain
Influenza caused by the H5N1 strain has thus far been rare. The U.S. Centers for Disease Control (CDC) has reported that more than 600 human H5N1 cases have been reported to WHO from 15 countries in Asia, Africa, the Pacific, Europe and the Near East since November 2003. Approximately 60 percent of individuals with documented H5N1 disease have died.

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