The prospect of a simple vaccination to prevent cervical cancer has moved a step closer with the publication of positive Phase II trial results on a candidate from Merck & Co, called Gardasil, in the April edition of the medical journal The Lancet Oncology.

Phase III clinical trials to evaluate Gardasil are already underway with over 25,000 participants enrolled worldwide, with results expected to be available later this year, and if successful Gardasil could be on the market in two years.

In the 227-woman study, Gardasil was able to reduce the incidence of several human papillomavirus strains that are linked to the development of both pre-cancerous lesions and genital warts. Over two and a half years of follow-up, Gardasil reduced the combined incidence of persistent infection from HPV-6, HPV-11, HPV-16, or NPV-18 – as well as related genital disease including new cervical pre-cancers and genital warts - by 90%. In absolute terms, there were 36 cases in the placebo group compared to just four among the women taking Gardasil.

Cervical cancer is one of the leading causes of cancer death amongst women around the world, with approximately 470,000 new cases and 230,000 deaths every year – almost 80% of which occur in developing countries. According to market research by Decision resources, the market for HPV treatments is expected to grow from $135 million dollars in 2002 to $1.4 billion in 2012, with prophylactic vaccines driving this growth [[03/12/03h]].

Six months ago, The Lancet also published a study of GlaxoSmithKline’s Cervarix vaccine, designed to protect against the HPV-16 and HPV-18 strains of the virus linked to cervical cancer. This study showed a 100% protection rate for the vaccine at six months [[15/11/04d]].

If approved, the availability of Cervarix and Gardasil could make it feasible to vaccinate young girls before they become sexually active and pick up HPV infection, although additional work needs to be done to establish safety and efficacy and – crucially – how long the protection will last.