GlaxoSmithKline’s cervical cancer vaccine Cervarix can protect women from the virus that causes the disease for up to four and a half years, according to clinical data reported in The Lancet.

Cervarix was found to stimulate antibodies against two types of human papillomavirus linked to 70% of all cases of cervical cancer - HPV-16 and HPV-18 – and maintain them at blood levels that could provide long-term protection against cervical cancer and the precancerous lesions that precede it, according to the authors, from Dartmouth Medical School in New Hampshire, USA.

"These findings set the stage for widescale adoption of HPV vaccination for prevention of cervical cancer," said Dr Diane Harper, who led the study.

GSK filed for approval of Cervarix in Europe last month, putting it in a race to market there with another HPV vaccine, Gardasil, developed by Merck & Co and partner Sanofi-Aventis. Gardasil has also been filed in Europe, and could reach the US market as early as June. Cervarix is not due to be filed in the USA until later this year.

Meanwhile, the Lancet researchers also say that Cervarix showed activity against two other strains – HPV-45 and HPV-31 – that together account for another 10% of cervical cancer cases. If confirmed, this could give GSK a marketing lever for Cervarix, allowing it to claim broader protection than its rival. Merck said it was also testing Gardasil against other HPV strains.

Analysts have suggested that Cervarix could achieve annual peak sales in the region of $2 billion, providing use of HPV vaccines comes into general use, while Gardasil could reach $3 billion, helped by first-to-market advantage and likely strong uptake in the US market.