The administration of the investigational vaccine, Gardasil, was shown to prevent all high-grade cervical precancers and non-invasive cervical cancers. The vaccine operates by fighting infection by the human papillomavirus (HPV), the cause of 70% of all cervical cancer.
The study compared Gardasil to placebo in 12,000 women aged between 16 and 26 who were not infected with HPV. Half the participants were given three doses of Gardasil spread out over a six-month period. The women were then monitored over two years to evaluate the effectiveness of the drug.
At the end of the trial none of the women who had been given the vaccine showed signs of cervical cancer. This was evaluated by monitoring the appearance of pre-cancerous lesions, a precursor of cervical cancer. Of the control group, 21 participants developed cervical cancer.
The trial, part of an ongoing study involving over 25,000 people worldwide, has been a huge success, putting Merck on target for submitting a licensing application to the FDA later this year. Sanofi is also likely to submit a European application for the vaccine. This will put the companies in direct competition with Britain’s GlaxoSmithKline for its product, Cervarix.
The companies are hoping Gardasil could be available within a year, a huge step in the fight against cervical cancer, which kills approximately 274,000 women worldwide every year. Merck estimates Gardasil could provide protection against as much as 87% of cervical cancer forming viruses and may eventually herald an end to the smear test.
The remaining debate will be at what age to vaccinate women. Although vaccination during adolescence is likely to be most effective, it has been alleged this could encourage underage sex.
Analysts say the vaccine could reach blockbuster status; good news for Merck which is still facing lawsuits over its withdrawn arthritis drug Vioxx.