According to an article recently published in The Lancet, the investigative vaccine CervarixTM is highly effective against the prevention of the human papillomavirus.
There are several different types of the human papillomavirus (HPV). HPV types 16 and 18 account for roughly 70% of all cases of cervical cancer. Cervarix (a bivalent L1 virus-like particle vaccine) is intended to prevent infection with these high-risk types of HPV, and may also offer some protection against two other high-risk types of HPV-types 45 and 31.
Because infection with HPV generally occurs soon after an individual becomes sexually active, vaccination at a young age-before sexual activity begins-is likely to offer the greatest protection. Over 20 million Americans are infected with some type of HPV virus. In most developing countries, most women are already infected with HPV, making development of a vaccine paramount in controlling this disease. It is also important to point out that HPV is associated with infections and cancers of other sites such as the vulva, vagina, anus, penis, and oropharynx. It is anticipated that vaccines against cervical HPV would also be effective for HPV infections in sites other than the cervix.
Researchers affiliated with the Papilloma Trial against Cancer in Young Adults study recently conducted a clinical trial to evaluate Cervarix in the prevention of HPV and pre-cancerous cervical sites. This trial included over 18,000 women between the ages of 15 and 25 years. Patients were treated with either Cervarix or a hepatitis A vaccine (control group). The first vaccine was followed by a second one month later, followed by a third vaccine six months later.
Trial results indicated that among patients treated with Cervarix, there were two cases of pre-cancerous sites on the cervix that were associated with HPV 16 or 18 compared with 21 cases in the control group.
The researchers concluded that Cervarix appears highly effective in preventing HPV and ultimately cervical cancer among women aged 15 to 25 years. Only future trials will determine the clinical utility of the already approved cervical cancer prevention vaccine Gardasil® as well as Cervarix.
Reference: Paavonen J, Jenkins D, Bosch FX, et al. Efficacy of a prophylactic adjuvanted bivalent L1 virus-like-particle vaccine against infection with human papillomavirus types 16 and 18 in young women: an interim analysis of a Phase III double-blind, randomised controlled trial. The Lancet 2007;369:2161-2170.