The vaccine has been approved for the prevention of pre-cancerous cervical lesions and cervical cancer causally related to human papillomavirus (HPV) (types 16 and 18), and formulated with GSK's novel AS04 adjuvant system is said to offer broad, extended protection to women given the jab. The AS04 adjuvant is formulated with aluminium hydroxide combined with a novel substance known as monophosphoryl lipid A (MPL). MPL directly activates key immune mechanisms, enhancing the initiation of the immune response by activating innate immunity leading to an improved cellular and humoral adaptive immune response, according to GSK.
"We believe our innovative adjuvant provides a real boost, with broader and longer-lasting protection for women," a GSK spokesperson told in-PharmaTechnologust.com. The adjuvant has been shown to offer significant benefits over traditional aluminium salt based adjuvants, such as the one used in Merck's Gardasil vaccine.
In clinical trials, Cervarix adjuvanted with AS04 compared to the same antigens adjuvanted with aluminium hydroxide alone showed antibody titres at least two fold higher (analysed up to four years after first dose), 'significantly higher' functional antibody titres (analysed up to four years after first dose), and B cell memory frequency approximately two fold higher (analysed up to two years after first dose). Data from a Phase III clinical study demonstrated that Cervarix provides 100 per cent protection against pre-cancerous lesions causally associated with HPV types 16 and 18, with long term data also showing 100 per cent sustained protection for up to five and half years after vaccination.
The vaccine will now be launched across the EU over the coming weeks, offering a new option to protect women against cervical cancer. "The real revolution Cervarix represents is the number of abnormal pap smears that it prevents," the GSK spokesperson commented.
"Many women jump to conclusions when they receive an abnormal result, the vaccine will help prevent this emotional turmoil." Head to head
So confident is GSK in its cervical cancer vaccine, that in January the company announced that it would be initiating and funding a head to head trial between Cervarix and Merck's high-profile vaccine, Gardasil. Over 1,000 women will be taking part in the trial, which will compare immune responses to cancer-causing virus types 16 and 18 in various age groups, as well as immune responses to other cancer-causing virus types.
The trial is "an indication of [GSK's] confidence in Cervarix' superiority," in-PharmaTechnologist.com was told, so Merck should perhaps keep an eye on the new vaccine and the challenge it could pose to its Gardasil franchise. Gardasil itself generated $723m (€513m) over the first half of this year, representing a major contribution to Merck's coffers and a key player in its vaccine portfolio.
Cervarix, however, may yet pose a threat to trailblazer's market share. US approval is anticipated in early 2008, with GSK also planning to apply to the World Health Organization to obtain prequalification status for Cervarix and make it available in developing countries where there is a very high incidence of cervical cancer.