Vaccin tegen baarmoederhalskanker: studie bewijst effectiviteit van vaccin tegen HPV virus - Human Papilloma Virus en indirect dus tegen ontwikkeling baarmoederhalskanker.

14 april 2005"Bron: The Lancet: Human Papillomavirus Quadrivalent Vaccine May Be Effective

Opnieuw bewijst een dubbelblinde gerandomiseerde studie - 277 jonge vrouwen (gemiddelde leeftijd, 20.2 ) kregen ca. 1,5 jaar het quadrivalent HPV vaccin, en 275 women (gemiddelde leeftijd, 20.0 jaar) kregen ca. 1,7 jaar een placebo - dat een vaccin tegen een HPV infectie zeer goed werkzaam kan zijn. 90% van de vrouwen in een studie bij ruim 200 vrouwen bleven vrij van deze vier HPV virussen die bijna altijd de bron zijn van beginnende baarmoederhalskanker

Resultaten: Vergeleken met de vrouwen die een placebo ontvingen hadden de vrouwen die het vaccin kregen toegediend 90% vermindering van infecties of ziekte veroorzaakt door het HPV virus 6,11,16 of 18. (95% confidence interval, 71% - 97%; P < .0001). Alle drie de vrouwen die externe genitale wondejes kregen en alle drie de vrouwen die eerste verschijnselen van baarmoederhalskanker ontwikkelden kwamen uit de controlegroep met placebo. Het vaccin was 100% effectief tegen eerste stadia van baarmoederhalskanker en genitale wrattten geassocierd met genoemde vier HPV virustypes. Er werden geen negatieve effecten van het vaccin gevonden of ervaren. De onderzoekers concluderen dat een vaccin dat de HPV virussen 6, 11, 16 en 18 bestrijdt, daarmee ook de genitale wratten en voorstadia van baarmoederhalskanker veroorzaakt door die vier virussen effectief kan voorkomen.

April 7, 2005 — Human papillomavirus (HPV) quadrivalent vaccine may be effective against persistent infection or disease, according to the results of a randomized, double-blind study published online April 7 in The Lancet Oncology. A large study is underway.

"In the developed world, full implementation of cervical-cancer screening has substantially shifted the burden of HPV infection from cervical cancer mortality to management of precancerous lesions,” lead author Luisa L. Villa, PhD, from Ludwig Institute for Cancer Research in Sao Paulo, Brazil, says in a news release. “In these countries, in addition to further reduction in incidence of cervical cancer, universal HPV vaccination might decrease the medical, psychological, and economic costs associated with the management of abnormalities detected by screening.”
This phase 2 study tested the efficacy of a prophylactic quadrivalent vaccine targeting HPV types 16 and 18, which are associated with 70% of cervical cancers, and types 6 and 11, which are associated with 90% of genital warts. The quadrivalent, L1 virus-like-particle (VLP) vaccine consisted of 20 µg type 6, 40 µg type 11, 40 µg type 16, and 20 µg type 18.
In this trial, Dr. Villa and colleagues randomized 277 young women (mean age, 20.2 ± 1.7 years) to receive quadrivalent HPV vaccine, and 275 women (mean age, 20.0 ± 1.7 years) were randomized to receive one of two placebo preparations at day 1, month 2, and month 6. Participants had regular gynecological examinations, cervicovaginal sampling for HPV DNA, testing for serum antibodies to HPV, and Papanicolaou testing for 36 months.
Analysis was primarily per protocol, and the primary outcome was the combined incidence of infection with HPV 6, 11, 16, or 18, or cervical or external genital disease, defined as persistent HPV infection, HPV detection at the last recorded visit, cervical intraepithelial neoplasia, cervical cancer, or external genital lesions caused by the HPV types in the vaccine.
Compared with women randomized to receive placebo, those randomized to receive vaccine had a 90% decrease in combined incidence of persistent infection or disease with HPV 6, 11, 16, or 18 (95% confidence interval, 71% - 97%; P < .0001). All three women with external genital lesions and all three with cervical intraepithelial neoplasia were in the placebo group. The vaccine was 100% effective against precancerous cervical lesions and genital warts associated with these four HPV types, and there were no serious adverse events related to the vaccine. The authors suggest that a vaccine targeting HPV types 6, 11, 16, 18 could substantially reduce the acquisition of infection and clinical disease caused by common HPV types.
Study limitations include lack of power to assess vaccine efficacy for the disease end points or for each HPV type separately, and duration of follow-up limited to three years.
“Inclusion of HPV 6 and 11 in a vaccine could also diminish the incidence of genital warts,” Dr. Villa says. “In developing countries that have not implemented screening programs for cervical cancer, a universal HPV vaccine could substantially reduce the incidence of the disease."
Merck, the developer of the quadrivalent HPV vaccine, funded this clinical trial, employs 10 of its authors, and has financial arrangements with several other authors.
Lancet Oncol. Published online April 7, 2005

. Reviewed by Gary D. Vogin, MD

vaccine, cervical, quadrivalent, genital, vaccin, infection, associated, lesions, baarmoederhalskanker, virussen