Merck & Co. have announced that their new vaccine against cervical cancer, Gardasil, was 100% effective in a phase III clinical trial.

Gardasil is directed against the two forms of human papilloma virus — HPV16 and HPV18 — that between them cause 70% of the 290,000 deaths worldwide from cervical cancer each year. The study followed 12,167 women aged 16–23 years. Among those who were given the vaccine, there were no cases of cancer caused by HPV16 or HPV18; in the controls, there were 21 cases. Margaret Stanley, of Cambridge University, said that “The results ... are so exciting because of the sheer size of the trial and the fact that it demonstrated 100% efficacy” (http://news.bbc.co.uk, 7 October 2005).

Merck hopes to get regulatory clearance for the drug in 2006, after which the vaccine could be widely given to adolescent women. Eliav Barr, of Merck, said that they were “... popping out the champagne corks” (http://www.timesonline.co.uk, 7 October 2005).

However, there are other cancer-causing strains of HPV against which Gardasil does not protect, causing Allan Hildesheim, of the National Cancer Institute, to warn that “This is not a panacea” (http://www.nytimes.com, 7 October 2005). Indeed, Merck have not disclosed how many vaccinated women in the trial developed forms of cervical cancer that were caused by other HPV strains.

Meanwhile, GlaxoSmithKline continues to work on its own cervical cancer vaccine, Cervarix.