New HPV Vaccine Offers Greater Protection Against Cervical Cancer Than Current Vaccine
A 9-valent HPV vaccine tested in broad spectrum HPV vaccine study
Scientists have developed a new human papilloma virus (HPV) vaccine which protects against 9 types of the virus, 7 of which cause most cases of cervical cancer. The new vaccine offers significantly greater protection than the current vaccine. A pivotal international clinical trial compared the safety and efficacy of the new 9-valent viruslike particle vaccine against HPV, with the current quadrivalent HPV vaccine in more than 14,200 women aged between 16 and 26 years.
Published in the New England Journal of Medicine, the study found that, among uninfected women, 9-valent HPV vaccine was 96.7% effective at preventing high-grade cervical, vulvar and vaginal disease caused by HPV 31, 33, 45, 52 and 58, and was equally effective as the current quadrivalent HPV vaccine in preventing diseases caused by HPV 6, 11, 16 and 18.
9-valent HPV vaccine offers the potential to increase overall cervical cancer prevention from 70% to 90%. However, it's crucial that vaccination must be done before exposure to the virus.
HPV is the most common sexually transmitted virus. Many people infected with HPV clear it from their systems with no lasting health concerns and some types of the virus are low risk, causing warts or verrucas. However, other types are high risk, causing cervical cancer and less commonly vulvar, vaginal, penile, anal, and throat cancers. Almost all cases of cervical cancer occur as a result of infection with high risk types of HPV.
Broad spectrum HPV vaccine study
The researchers performed a randomised, international, double-blind, phase IIb–III study. Women received the 9-valent HPV vaccine or the quadrivalent HPV vaccine in a series of 3 intramuscular injections on day 1 and at months 2 and 6.
Serum was collected for analysis of antibody responses. Swabs of labial, vulvar, perineal, perianal, endocervical, and ectocervical tissue were obtained and used for HPV DNA testing, and Papanicolaou testing was performed regularly.
Tissue obtained by biopsy or as part of definitive therapy, including a loop electrosurgical excision procedure and conisation, was tested for HPV.
The rate of high-grade cervical, vulvar, or vaginal disease irrespective of HPV type in the modified intention-to-treat population was 14.0 per 1000 person-years in both vaccine groups.
The rate of high-grade cervical, vulvar, or vaginal disease related to HPV-31, 33, 45, 52, and 58 in a susceptible population was 0.1 per 1000 person-years in the 9-valent HPV group and 1.6 per 1000 person-years in the quadrivalent HPV group, giving an efficacy of the 9-valent HPV vaccine of 96.7%.
Antibody responses to HPV-6, 11, 16, and 18 were non-inferior to those generated by the quadrivalent HPV vaccine. Adverse events related to injection site were more common in the 9-valent HPV group than in the quadrivalent HPV group.
The 9-valent HPV vaccine did not prevent infection and disease related to HPV types beyond the 9 types covered by the vaccine.
Following important findings, new vaccine has been licenced in the USA and approval is currently being sought in other countries.
This clinical trial was funded by Merck.
Joura EA, Giuliano AR, Iversen O-E, et al. A 9-Valent HPV Vaccine against Infection and Intraepithelial Neoplasia in Women. N Engl J Med 2015; 372:711-723. DOI: 10.1056/NEJMoa1405044