UPDATE 1-Glaxo prepares to launch Cervarix after EU okay

(Adds company comment on launch plans, background)

LONDON, Sept 24 (Reuters) - GlaxoSmithKline GSK.L said on Monday the European Commission had approved its cervical cancer vaccine Cervarix, clearing the way for the European launch of one of its key new products.

The move had been expected after a panel of experts at the European Medicines Agency recommended the vaccine in July.

Glaxo's shot will compete with U.S.-based Merck & Co's MRK.N Gardasil which is already available in both the United States and Europe, where it is sold via a vaccine joint venture with France's Sanofi-Aventis SASY.PA.

Both vaccines protect against cancer-causing strains of the sexually transmitted human papillomavirus (HPV).

A spokeswoman for the British-based group, the world’s second-largest drugmaker, said Cervarix would go on sale in major European markets shortly.

“We intend to launch across Europe within the next few weeks,” she said.

Glaxo decline to reveal how much it would charge for Cervarix or whether the European price would be above or below that in Australia, where the vaccine won its first major regulatory approval in May.

Cervarix is not likely to go on sale in the key U.S. market before 2008, since it was only submitted to the U.S. Food and Drug Administration in March.

Governments around the world have endorsed the concept of vaccinating young girls against HPV, although some groups oppose the idea of routine vaccination against a sexually transmitted virus.

The two vaccines are each expected to become multibillion-dollar-a-year sellers, although many analysts believe Merck’s first-mover advantage may win it the lion’s share of the business.

Glaxo, however, thinks it could have an edge due to the novel adjuvant, or additive, used in Cervarix, which may mean it is more potent and lasts longer.

The British group announced in January it had started a head-to-head study comparing Cervarix and Gardasil to see which shot produces the best immune response to cancer-causing HPV types 16 and 18.