Glaxo says Cervarix shows effect for over 6 years

LONDON, March 10 (Reuters) - GlaxoSmithKline Plc (GSK.L) said on Monday its cervical cancer vaccine Cervarix provided significant protection for women against the four most common cancer-causing human papillomavirus (HPV) types for 6.4 years, the longest duration of protection reported to date.

Data at the Society of Gynecologic Oncologists annual meeting in Tampa, Florida, showed the vaccine was 100 percent effective in preventing precancerous lesions due to virus types 16 and 18. It also provided substantial protection against infection caused by types 31 and 45.

Europe's biggest drugmaker plans to give additional data focusing on neutralising antibodies in the coming months. Neutralising antibodies are viewed as critical for protecting women against cancer-causing virus types over time.

Cervarix, which is marketed in Europe but is still awaiting approval in the United States, is a competitor to Merck & Co Inc's (MRK.N) successful product Gardasil.

Both vaccines are designed to be given to girls and young women to protect against cancer-causing strains of HPV.

Cervarix is viewed as a key new product for Glaxo, with multibillion-dollar-a-year sales potential.

However, a decision in December by the U.S. Food and Drug Administration to delay its approval knocked some investors' confidence. Glaxo says it aims to update the U.S. regulator on Cervarix during the second quarter of 2008. (Reporting by Ben Hirschler; Editing by David Holmes)