THE world's first cancer vaccine, which is 100 per cent effective at preventing most kinds of cervical cancer, will be available by next year, an international drug firm announced yesterday.
Cervical cancer kills about half of the 3,000 women a year in the UK who contract it.
But the vaccine, called Gardasil, has been shown in trials - involving 12,167 women from 13 countries including the UK - to protect against two types of human papillomavirus (HPV), which cause some 70 per cent of cervical cancers.
Gardasil, a collaboration between pharmaceutical firms Merck & Co Inc and Sanofi Pasteur, would be the first ever vaccine that protects against cancer to come on to the market.
However the vaccine is controversial because it is most effective when given before people start having sex. The company believe 12 or 13 would be the most effective age, but critics have claimed this could encourage under-age sex.
Dr Eliav Barr, Merck's head of clinical development for Gardasil, said: "To have 100 per cent efficacy is something that you have very rarely. We're breaking out the champagne."
Merck plans to seek approval to sell its vaccine for use by girls and young women by the end of this year in US and Europe.
"If all goes well, sometime in 2006 it should be on the market," Dr Barr said.
Merck is continuing research on Gardasil and will report on four years of follow-up investigations on women in the study.
The company also will explore whether the vaccine's effectiveness wanes over time.
Dr Barr noted that some women in the study developed dangerous precancerous lesions caused by HPV types other than two which Gardasil targets.
A second analysis, including hundreds more women participating an the ongoing study of 25,000 women, showed that after just one dose the vaccine was 97 per cent effective.
Dr Laura Koutsky, the principal investigator at the HPV research group at Washington University in Seattle, said: "These are the first pivotal data to show that vaccination with Gardasil reduced HPV 16 and 18 [the two types] related cervical pre-cancer and non-invasive cervical cancer."
She added that she hoped the vaccine would eventually be improved to protect against up to another half dozen types of the virus that cause cervical cancer.
"In that case, you could be blocking viruses that cause 87 per cent of cervical cancer cases, instead of 70 per cent," Dr Koutsky said.
More than 400,000 women contract HPV in Britain a year but only a small percentage get cervical cancer as a result.
Commenting on the findings, Dr Anne Szarewski, clinical consultant at Cancer Research UK, said Gardasil had shown good results in previous trials and appeared to be "fulfilling its promise".
"An awful lot of pharmaceuticals show early promise and then fall by the wayside, but this is going from strength to strength," she said.
"These results add to the mounting evidence that cervical cancer vaccines offer great promise for the future.
"By using HPV vaccines it appears we may soon be able to prevent the majority of cases. With any disease caused by a virus, the best way to stop it is to prevent it with a vaccine."
Dr Szarewski said, apart from preventing deaths, one of the main benefits would be removing the fear of hundreds of thousands of women who test positive for HPV that they will develop a highly lethal cancer.
Professor Margaret Stanley, an expert on HPV from Cambridge University, said: "We now have evidence that Gardasil is effective against the advanced-stage abnormalities of the cervix, called lesions, that lead to invasive cervical cancer.
"The smaller-scale preliminary HPV vaccine trials published to date have only indicated that this may be the case, but this study gives us very solid evidence.
"The results are so exciting because of the sheer size of the trial and the fact that it demonstrated 100 per cent efficacy."
Gardasil and the rival Cervarix vaccine, being developed by GlaxoSmithKline, could be among the biggest-selling drugs of all time. One analyst estimated Gardasil could be worth 567 million a year. Merck shares rose nearly 6 per cent yesterday.