GlaxoSmithKline’s (GSK) candidate cervical cancer vaccine, Cervarix, formulated with the proprietary adjuvant AS04, induced antibody levels against the two most common cancer-causing HPV types (HPV 16/18) at least two-fold higher in 10-14 year old adolescent girls, than in women aged 15-25 years, a new study showed.

The candidate vaccine for cervical cancer was also shown to induce antibodies in 100 per cent of volunteers in both age groups one month after completion of the course of vaccination. The vaccine in the present study was well tolerated and adverse event rates were similar in each age group. No vaccine-related serious adverse events were reported, states a GSK release.

Recent positive findings have demonstrated that the AS04 adjuvant in the candidate vaccine induces a stronger, sustained immune response when compared to a formulation with aluminium salt alone in young adult women. The higher antibody levels observed in the adolescent group compared to that observed in women 15-25 years old are important as the elevated levels demonstrated in this younger age range may result in longer duration of protection. It would be beneficial to vaccinate adolescents against infection with cancer-causing HPV types 16/18 well before the start of sexual activity with a vaccine with sustained efficacy.

The study was designed specifically to compare the immunogenicity and safety of the candidate vaccine in the younger 10-14 year old group with the 15-25 year old group.

"Vaccination of pre-adolescent girls against cancer-causing HPV before onset of sexual activity will be an important part of the overall strategy for cervical cancer prevention," said Anna-Barbara Moscicki, professor of paediatrics, University of California, San Francisco.

"Prevention of high-risk HPV 16 and HPV 18 infection is a key to reducing cervical cancer, and a prophylactic vaccine against these types of HPV is necessary to prevent infection in the first place. The higher levels of antibody titers seen in the vaccinated teens than the vaccinated adults offers encouraging evidence that in this age group, a stronger immune response could translate into longer protection. Ongoing studies should further demonstrate these findings," added Moscicki.

HPV is the leading cause of cervical cancer. Globally, approximately 70 per cent of all cervical cancer cases are associated with just these two cancer-causing types, HPV 16 and HPV 18. GSK’s cervical cancer vaccine candidate targeting HPV 16/18 is currently undergoing phase III clinical trials involving more than 30,000 women worldwide.

Cervical cancer is a major global health problem, with nearly 5, 00,000 new cases occurring each year worldwide. It is the second most common cancer and the third leading cause of cancer deaths in women worldwide.