Human papilloma virus (HPV) is the most common sexually transmitted infection in the United States. The Centers for Disease Control and Prevention estimates that about 6.2 million Americans are infected with genital HPV each year and that over half of all sexually active men and women become infected at some time in their lives. While most HPV infections are cleared by the body's own defense system and do not lead to cancer, virtually all cases of cervical cancer are linked to HPV infection.
On average, there are 9,700 new cases of cervical cancer and 3,700 deaths attributed to HPV in the United States each year. Worldwide, cervical cancer is the second most common cancer in women, and is estimated to cause over 470,000 new cases and 233,000 deaths each year.
Nearly two decades ago, researchers at the NCI, part of the National Institutes of Health (NIH), showed that a structural protein from the surface of an HPV serotype causally linked to the development of cervical cancer can self assemble into virus like particles (VLPs) that stimulate protective immune responses to HPV without causing infection. The NIH facilitated translation of this discovery into a commercial human vaccine by overseeing the patenting of the VLP technology and licensing it to Merck and Glaxo SmithKline (GSK). The resulting vaccines trigger the immune system to produce protective antibodies that bind the virus, thereby thwarting viral infection of cervical cells and subsequent cancers.
Clinical trials of Gardasil™, the Merck vaccine, demonstrated 100% protection against the development of precancerous cervical lesions and nearly complete protection against the development of genital warts.In June2006, the Food and Drug Administration approved Gardasil™ for the prevention of cervical pre–cancer, cancer, and genital warts.
A GSK vaccine (Cervarix™) that is also based on NCI's VLP technology has been submitted for regulatory approval in Europe. HPV vaccination is expected to translate into public health benefits in the U.S. by complementing existing cervical cancer screening, and reducing the medical care followup and invasive procedures associated with abnormal Pap smears as well as related health care costs. In poorly resourced regions of the world, HPV immunization may prevent several hundred thousand cancers annually, many of which affect relatively young women. The vaccine may offer far greater benefits in the developing world because the burden of disease is greatest and other preventive approaches to cervical cancer are limited or nonexistent.