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Nine-Valent HPV Vaccine May Prevent Nearly 90% of Cervical Cancers
Because nine human papillomavirus (HPV) subtypes have been found to cause most cervical precancers, a nine-valent HPV vaccine currently being investigated may be able to prevent more cervical cancers than current vaccines, according to research published in Cancer Epidemiology, Biomarkers, and Prevention.
“We wanted to study how many cervical precancers could potentially be prevented by an investigational nine-valent HPV vaccine that provides protection against the HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58,” said lead investigator Elmar A. Joura, MD, of the Medical University of Vienna in Austria. “Approximately 85% or more of precancerous lesions of the cervix were attributed to the nine HPV types covered in the vaccine; therefore, if nine-valent HPV vaccination programs are effectively implemented, the majority of these lesions could be prevented.”
“Given the high vaccine efficacy that was observed in a large phase III clinical trial testing the nine-valent HPV vaccine, if vaccination programs with this new-generation vaccine are effectively implemented, approximately 90% of invasive cervical cancer cases worldwide could be prevented, in addition to the majority of precancerous lesions,” Joura added.
HPV types 16 and 18 are the predominant causative factors in cervical precancers, which are referred to as CIN 1, 2, and 3, depending on the extent of the abnormality. In 2011, the International Agency for Research on Cancer (IARC) expanded the list of carcinogens to include HPV types 31, 33, 35, 39, 45, 51, 52, 56, 58, and 59.
“Despite the clear safety profile of the currently disseminated HPV vaccines, uptake in the United States and other resource-rich countries has been inadequate,” Joura said. “To achieve the population-level potential of the HPV vaccine to reduce cancer, vaccine uptake must increase.”
Joura and his colleagues used data from 12,514 women, aged 15 to 45 years, enrolled in the placebo arms of three clinical trials testing a quadrivalent HPV vaccine. Among these women, 2,507 were diagnosed with CIN1, CIN2, CIN3, or adenocarcinoma in situ (AIS). The researchers estimated the number of precancers harboring the HPV types included in an investigational nine-valent HPV vaccine being developed by Merck and currently under review at the FDA.
After adjusting for the presence of multiple HPV subtypes in a single lesion, they found that seven high-risk HPV types included in the nine-valent vaccine were present in about 55% of CIN 1, in about 78% of CIN 2, in about 91% of CIN 3, and in nearly 100% of AIS lesions.
Of the women aged 15 to 26 years who had precancers, 54% had a single HPV infection, and 32% were infected with more than one HPV type. Of those aged 24 to 45 years with precancers, 59% and 19% were infected with one or more than one HPV types, respectively.
Source: AACR; October 1, 2014.