Merck says Gardasil vaccine protects older women

CHICAGO (Reuters) - Gardasil, Merck's vaccine for preventing cervical cancer in girls and women aged 9 to 26, may offer protection for women up to age 45, the company said on Sunday.

In a study of 3,800 women aged 24 to 45, the vaccine prevented 91 percent of cases of persistent infection, minor cervical abnormalities, pre-cancers and genital warts caused by four strains of the sexually transmitted human papillomavirus, or HPV.

"This is the first efficacy study in this age population," Dr. Eliav Barr, who heads the Merck HPV Vaccine program, said in a telephone interview. "The vaccine performed as we expected. It was highly effective."

Merck directed and funded the study.

Gardasil is designed to protect against HPV types 16 and 18, which are known to cause about 70 percent of all cases of cervical cancer. It also protects against HPV strains 6 and 11, which cause genital warts.

It is approved for use in girls and women ages 9 to 26, but Merck is seeking to expand its use to older women.

GOAL IS FDA APPROVAL

The study, presented at the 24th International Papillomavirus Conference in Beijing, China, found that Gardasil prevented 83 percent of infections, cervical abnormalities and pre-cancers and external genital lesions caused by the cancer-causing HPV types 16 and 18.

It reduced 94 percent of abnormal Pap tests caused by these HPV types, and prevented 100 percent of these problems caused by the genital wart HPV strains 6 and 11.

The women were followed for more than two years after the six-month vaccination period. The company plans to continue to follow them for a total of four years.

Merck will use these data to seek U.S. Food and Drug Administration approval to market the vaccine to women through age 45.

GlaxoSmithKline, meanwhile, said new research showed its rival vaccine Cervarix effectively induced antibodies to HPV in the cervix -- the only place where the virus can evade the immune system and replicate -- two years after vaccination.

Tino Schwarz of the University of Wuerzburg, Germany, said the finding proved Cervarix provided protection where it was most needed.

Cervarix was approved in Europe and Australia this year but is still awaiting a green light by the FDA.

Cervical cancer is the second most common type of tumor in women and the leading cause of cancer death in some countries.

More than a quarter of U.S. girls and women aged 14 to 59 are infected. About 90 percent of infections clear within two years.

(Additional reporting by Ben Hirschler in London)