More trial data backs Merck's cervical cancer shot

LONDON (Reuters) - New data from a combined analysis of four Phase II/III studies involving more than 20,000 women confirm the effectiveness of Merck & Co Inc's cervical cancer vaccine Gardasil, researchers said on Thursday.

Gardasil sustained 98 to 100 percent efficacy in preventing vaccine virus type-related precancerous cervical lesions in young women.

"The results ... include by far the longest follow-up for any cervical cancer vaccine in large Phase III studies and strongly substantiate the evidence that the protection provided by Gardasil will be long-lasting," said Elmar Joura of the University of Vienna.

The new data were presented at the 19th International Congress on Anti-Cancer Treatment in Paris.

In light of the high efficacy, the independent monitors of the Phase III trials have recommended the studies be terminated in order to provide the benefits of Gardasil to the women in the placebo group.

Gardasil is sold by Merck in the United States and in Europe by Sanofi Pasteur MSD, a 50/50 joint venture between Sanofi-Aventis SA and Merck.

It competes in Europe against GlaxoSmithKline Plc's rival product Cervarix, which has yet to be approved in the United States.

Both vaccines are designed to be given to girls and young women to protect against cancer-causing strains of the sexually transmitted human papillomavirus (HPV).

(Reporting by Ben Hirschler, editing by Will Waterman)