GlaxoSmithKline has secured US approval for a second four-strain (quadrivalent) influenza vaccine in time for the upcoming flu season.
The latest approval is for Flulaval Quadrivalent, which has been given the OK by the FDA for use in patients aged three years or over to protect against A and B strains of seasonal influenza.
AstraZeneca was the first pharma company to get a four-strain vaccine approved in the US when its Medimmune division won approval for its FluMist Quadrivalent product in people aged between two and 49 years of age.
GSK joined the club when its Fluarix Quadrivalent was approved by the FDA last December, and since then Sanofi has also been given a green light for its Fluzone Quadrivalent, giving three of the top four flu vaccine producers in the US a four-strain product ahead of the 2013-14 flu season.
Notable by its absence is Novartis, which is now lagging behind its competitors in the shift from trivalent vaccines.
Instead, the Swiss firm has focused its R&D investment on switching from egg-based to cell culture-based production, securing approval for its FluCelVax product in November 2012.
For years, seasonal flu vaccines have used two influenza A strains and one B strain, with the specific strains to be used recommended each year by the World Health Organization (WHO). This year the WHO also made recommendations for quadrivalent vaccines with an additional B strain.
All told some six companies make flu vaccine to meet US demand, and it is estimated that this year around 25m doses of the 135m-140m distributed in the country will be four-strain vaccine.
The US Centers for Disease Control and Prevention (CDC) has ordered 8.4m doses of quadrivalent flu vaccine and a little under 10m doses of trivalent vaccines.
GSK has said it anticipates making only a limited amount of quadrivalent vaccine available this year, although it should be able to supply around 35m doses for the 2014–15 flu season. The new Flulaval product is presented in multidose vials while Fluarix is delivered in prefilled syringes.
The upgrade should be good news for the vaccine manufacturers as quadrivalent vaccines typically cost around 50 per cent more than their trivalent predecessors. Last year, GSK posted flu vaccine sales of £200m, down around 11 per cent thanks to lower sales to the US healthcare system.