The U.S. Food and Drug Administration has asked Merck & Co., maker of the Gardasil vaccine against cervical cancer, to provide longer-term data on women aged 27 to 45, the company said Friday.

The request came as the FDA again withheld approval of Merck's request to expand the use of the vaccine to include women in that age range.

Gardasil is currently approved in Canada and the U.S. for females aged nine to 26 for the prevention of infection caused by four types of the human papillomavirus or HPV.

The FDA recommended that the company submit data when its 48-month study on the older group of women is done. Merck said it expects to give a response in the fourth quarter of 2009.

In June, the agency turned down Merck's application for women aged 27 to 45 and asked for more information on the vaccine's effectiveness.

The latest request from the FDA does not affect Gardasil's approved use in younger females, or Merck's application to expand its use to males between the ages of 16 and 26.

By 2008, all provinces had school-based vaccination programs for Gardasil, which costs $360 US for a course of three treatments.

Studies suggest the vaccine is most effective before sexual activity begins, since that increases the chance of exposure to the sexually transmitted virus.

A competitor's vaccine, GlaxoSmithKline's Cervarix, is approved for use in some countries, but not in Canada or the U.S.

With files from the Associated Press