Cervarix has been shown to be 100% effective in preventing infection with HPV strains 16 and 18, which together cause about 70% of cervical cancer cases. Researchers in a 2006 study published in the online edition of the Lancet also found that Cervarix prevented infection with HPV strains 31 and 45, which together with strains 16 and 18, cause more than 80% of cervical cancer cases.

The Australian Therapeutic Goods Administration in June approved the vaccine for girls and women ages 10 to 45, and the European Committee for Human Medicinal Products last month recommended the vaccine for sale and marketing in the European Union. FDA has granted a standard 10-month review of the vaccine and most likely will take action on GSK's application in January 2008, according to analysts at Evolution Securities.

Study, Reaction

For the study, Allan Hildesheim, a senior investigator at NCI, and colleagues between June 2004 and December 2005 enrolled 2,189 women ages 18 to 25 in Costa Rica who tested positive for HPV DNA at the time of enrollment. About half of the women in the study were given Cervarix and half were given the hepatitis A vaccine.