MANILA, Philippines - The final analysis of the largest efficacy trial of a cervical cancer vaccine confirmed that GlaxoSmithKline’s vaccine is highly effective not only in protecting against the two most common cervical cancer-causing human papillomavirus (HPV) types, 16 and 18, but also for other most common cervical cancer causing HPV types.
Published recently in the medical journal The Lancet, the study also showed that the GSK vaccine provides individual cross-protection against HPV types 31, 33 and 45, the three most common cancer-causing virus types beyond 16 and 18.
The study further validates earlier results demonstrating that the GSK vaccine provided cross protection against 12 other cancer-causing types other than HPV 16 and 18. It is estimated that approximately 15 types of HPV may cause cervical cancer.
The study involved a total of 18,644 women, aged 15 to 25, from 14 countries across Europe, the Asia-Pacific and Latin and North America, with more than 2,400 women coming from the Philippines.
Sally Gatchalian, GSK medical affairs director, said, “This is really good news for women at risk here in the Philippines, where cervical cancer remains the second highest killing cancer for women. These excellent study results confirm the efficacy offered by GSK’s cervical cancer vaccine against HPV 16 and 18.”
“For the first time, the results show that this vaccine is effective against cervical pre-cancers associated with the most common cancer-causing virus types beyond HPV 16 and 18. It’s also good news for the primary prevention of cervical cancer as it indicates the vaccine could offer women additional protection against cervical cancer beyond what had at first been anticipated,” she said.
This additional efficacy could translate into approximately 11 to 16 percent extra protection against cervical cancer over and above the protection afforded by efficacy against HPV 16 and 18 alone. This effect was mainly driven by protection against HPV types 31, 33 and 45.
HPV types 16, 18 and 45 are particularly important because these types are associated with nearly 90 percent of cases of adenocarcinoma, a very aggressive type of cervical cancer more common in younger women and more difficult to detect through screening.
Professor Jorma Paavonen, of the University of Helsinki, Finland, principal investigator of the study and lead author of the publication, said, “The results show GSK’s vaccine is highly effective against the most common cervical cancer-causing virus types and has the potential to substantially reduce the incidence of cervical pre-cancers, cervical cancer and the associated diagnostic and surgical procedures. The results re-affirm confidence in vaccination as a primary preventative measure against cervical cancer when used alongside screening.”
Results from another study show that the GSK vaccine has induced consistently high levels of antibodies against virus types 16 and 18 over a 7.3-year period.
This is the longest duration of consistently high immune response shown by a cervical cancer vaccine against the two most common cancer-causing virus types to date.
Unlike other vaccines, GSK’s cervical cancer vaccine shows no signs of waning, which assures women that they get the same high level of protection even beyond seven years. Modeling studies predict that these levels may last up to 20 years.
Women remain vulnerable to HPV infection and the potential development of cervical lesions throughout their life so it is essential for vaccines against cervical cancer to provide long-term protection.
GSK’s cervical cancer vaccine is formulated with the innovative adjuvant system AS04, specifically designed and selected to enhance the immune response against HPV, which is responsible for cervical cancer.
Adjuvants are substances used to enhance the immune system’s response to an antigen, and data show that GSK’s cervical cancer vaccine, adjuvanted with AS04, induces a stronger and more sustained immune response compared to the same vaccine antigens adjuvanted with conventional aluminium hydroxide alone.
Cervical cancer currently ranks as the second highest killer cancer among women in the Philippines, claiming an estimated 4,300 lives out of the 6,000 cases reported each year.
Vaccination, coupled with regular screening, is considered a key way in which women can protect themselves from this deadly disease.