EU approves its first prepandemic H5N1 vaccine

May 19, 2008 (CIDRAP News) – An H5N1 influenza vaccine made by the British pharmaceutical company GlaxoSmithKline (GSK) has become the first prepandemic vaccine to be licensed by the European Union (EU), the company announced today.

The European Medicines Agency has approved the adjuvanted vaccine, called Prepandrix, for marketing in all 27 EU countries, GSK said in a news release. The vaccine offers European governments the opportunity to protect their populations "in advance or at the outset of a declared influenza pandemic," the company said. The product is licensed for adults aged 18 to 60.

The EU approval comes about 13 months after the US Food and Drug Administration approved the first H5N1 vaccine for the United States, made by Sanofi Pasteur.

"This vaccine marks a significant step in the world's ability to cope with an influenza pandemic," GSK CEO Jean-Pierre Garnier said in the release.

Disease experts hope that prepandemic vaccines, based on existing H5N1 strains, will offer some protection against an emerging pandemic strain of H5N1 until a specific pandemic vaccine can be developed and produced, a process expected to take 4 to 6 months.

The EU approval is based on studies of a version of the vaccine involving an H5N1 strain isolated in Vietnam in 2004 (a clade 1 strain), the company said. Results of animal and human studies suggest that the vaccine may also offer protection against clade 2 strains of the virus.

The vaccine contains an oil-and-water adjuvant that enables it to induce what is believed to be a protective immune response at low doses, according to published results. For example, two 3.8-microgram (mcg) doses generated immune responses that met all US and European criteria for vaccine licensing, according to findings published last August in The Lancet. By comparison, seasonal flu vaccines contain 15 mcg of antigen for each flu strain targeted.

In addition, more than 75% of volunteers who received two 3.8-mcg doses of the vaccine were shown to have neutralizing antibodies against a clade 2 strain of H5N1, the Lancet report said.

GSK announced last year it would donate 50 million doses of its H5N1 vaccine to the World Health Organization (WHO) to help launch an international prepandemic vaccine stockpile.

The company said it has already sold supplies of its vaccine to the United States, Switzerland, and Finland. Officials said sales in 2007 totaled 146 million British pounds (US $284 million).

The WHO said last week that at least 16 companies have H5N1 vaccines in advanced development.

See also:

May 19 GSK news release

Aug 27, 2007, CIDRAP News story "Trial results for Glaxo's H5N1 vaccine released"

Apr 17, 2007, CIDRAP News story "FDA approves first H5N1 vaccine"

May 16 CIDRAP News story "Launch of WHO H5N1 vaccine stockpile still awaited"

CIDRAP News seven-part article series "The pandemic vaccine puzzle"

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