A recent study published in the Lancet Oncology reports that an investigational vaccine against the human papilloma viruses (HPV) significantly reduces the incidence of the infections that are responsible for 70% of all cases of cervical cancer.
It is estimated that 20 million men and women are infected with HPV. In some cases, HPV is self-limiting and will go away without treatment. However in some cases, HPV has been associated with cervical cancer, abnormal pap smears and genital warts. In the US alone, an estimated 10,000 new cases will be diagnosed in 2005. Genital warts are also common, with 500,000-1 million cases each year in the US.
In this recent phase II study, double blind, 552 women from the United States, Europe, and Brazil were randomized to receive either the vaccine known as Gardisil, or a placebo. Doses were given on day 1, month 2 and month 6, to determine if the vaccine would decrease the incidence of human papilloma viruses’ 6, 11, 16 and 18, as well as other types of pre-cancerous cervical diseases such as genital warts, and cervical intraepithelial neoplasia. During the 2 ½ years of follow up after vaccination, Gardasil was found to reduce the incidence of HPV, related genital diseases and pre-cancerous lesions by 90% when compared to the placebo group. The success of the vaccine was determined by the immune response, which was measured by the anti-HPV serum tests. Researchers found that antibody levels were higher among the women who had received the vaccine when compared to the placebo group. Although these levels began to decline after the 7th month, overall levels remained higher at 3 years than the placebo group.
Researchers concluded that Gardasil is a promising new option for the treatment and prevention of HPV as well as other genital diseases and pre cancerous lesions. Further clinical trials are underway, with over 25,000 enrolled world wide, and results are expected later this year.
Villa L, Costa R, Petta C, et al. Prophylactic quadrivalent human papillomavirus (types 6, 11, 16, and 18) L1 virus-like particle vaccine in young women: a randomised double-blind placebo-controlled multicentre phase II efficacy trial. The Lancet Oncology. 2005. Early on-line publication. Available at: http://oncology.thelancet.com/journal. Accessed April 2005.