October 20, 2009- Bethesda, Maryland- The FDA has approved a second vaccine to prevent cervical cancer and cervical precancers, the vaccine's manufacturer, GlaxoSmithKline (GSK), announced last week. The approval is based on data from a large clinical trial showing that the vaccine, Cervarix, prevented precancerous lesions in 93 percent of those who received the full vaccine sequence of three injections over 6 months.
Cervarix is a bivalent vaccine, meaning it is specifically designed to protect against two human papillomavirus (HPV) types, HPV 16 and 18, which together are responsible for three-quarters of cervical cancers in North America. Clinical trial data also indicate that Cervarix offers more modest protection against precancerous lesions associated with HPV 31, GSK explained in a statement, as well as other tumor-causing (or oncogenic) HPV types. The company expects the vaccine to be available in the United States by the end of the year.
The FDA last week also approved the HPV vaccine Gardasil for the prevention of genital warts in boys. Gardasil is already approved and is being actively used in girls and young women for the prevention of cervical cancer. Gardasil is a quadrivalent vaccine that is designed to specifically protect against infections with four HPV types: 16, 18, 6, and 11. HPV types 6 and 11, which are not considered to be oncogenic, cause genital warts.
The agency's approval of Gardasil for boys aged 9 to 26 is based on data from a randomized clinical trial of more than 4,000 males aged 16 to 26, which demonstrated 90 percent protection against HPV 6- and 11-related genital warts. In a press statement announcing the approval, the FDA explained that for boys aged 9 to 15, studies have been conducted to measure their immune response to the vaccine, and the results showed that the immune response was as good as that found in the 16- to 26- year-old age group, indicating that the vaccine should have similar effectiveness.
A number of studies have now linked infection with HPV 16 to certain types of head and neck cancers,in particular oropharyngeal cancer (the tonsils and base of the tongue), the rates of which have been increasing over the last decade. So there is a chance, some researchers believe, that widespread HPV vaccination of both males and females could have a broader cancer prevention effect.
"There is every reason to be optimistic that vaccination may help us to reduce the current trends of HPV-related tonsillar cancer," said Dr. Maura Gillison, a researcher at Ohio State University who was among the first to identify the link between HPV and head and neck cancer. Dr. Gillison said she is hopeful that a clinical trial can be launched in the near future to assess whether vaccination can prevent oral HPV 16 infections.
The CDC's Advisory Committee on Immunization Practices, which makes recommendations on the administration of FDA-approved vaccines to the medical community, will decide later this week whether to recommend that males be vaccinated against HPV to prevent genital warts.