A Colombian study has revealed that Merck & Co’s cervical cancer vaccine Gardasil has a beneficial effect in women aged 24 to 45. However, following a ruling against the vaccine in June 2008, Merck & Co will first have to present 48 months of continuous study data to the FDA before it can be reconsidered for approval for use within this potentially lucrative market.

Gardasil protects against infection with human papillomavirus (HPV) types 6, 11, 16 and 18. While HPV6 and 11 are associated with genital warts, HPV16 and 18 cause approximately 70% of cervical cancer cases. The peak incidence of HPV generally occurs within five to 10 years of first sexual experience; Gardasil has been approved since 2006 for girls aged nine to 26 years, however, the vaccine does not protect those who have already been infected.

Gardasil is currently the market leader in the cervical cancer vaccine field, with global sales of $2.3 billion in 2008, although growth has slowed after strong initial sales in 2006-07 due to a less-than-expected uptake in the catch-up population. Aiming to extend the vaccine’s market potential to additional age groups, Merck is seeking to expand its use to women aged 24 to 45 years. However, the FDA rejected a previous filing for this age group in June 2008, and has requested 48-month efficacy data, which are expected later this year.

Researchers at the National Institute of Cancer in Bogota, Colombia have now reported data from a study investigating Gardasil in over 3,800 women aged 24 to 45 years. Study results indicate that women aged 24 to 45 years with no history of cancer-causing genital warts or cervical disease were significantly less likely to become infected with HPV if they received Gardasil than women who received placebo injections. After a mean follow-up time of 2.2 years, the efficacy of Gardasil in preventing disease or infection related to the vaccine serotypes was more than 90% in this age group.

Even if this study shows that Gardasil is of medical benefit to older women, full 48-month data will be required for the FDA to reconsider approval for the vaccine in this age group. In addition, more data is needed regarding the cost-efficacy of Gardasil in this population, particularly since screening of patients for existing HPV infection may be required, which would further increase the already substantial costs of the vaccine. In light of this, Datamonitor believes that while a future widespread recommendation of HPV vaccination for older women is questionable, this age group may become a promising private sector opportunity.