The Food and Drug Administration has approved GlaxoSmithKline PLC's (GSK) Cervarix vaccine designed to protect against cervical cancer in women, the company said Friday.

The vaccine will compete against Merck & Co.'s (MRK) Gardasil, which was approved in 2006. FDA's approval follows a recommendation by an outside panel of medical experts in September. The panel said the vaccine was safe and effective at preventing an infection that can cause cervical cancer in women as well as a precancerous condition that can lead to cervical cancer.

The vaccine is approved for use in girls and women ages 10 to 25.

Cervarix is designed to protect against cervical cancer and other conditions linked to two strains of human papillomavirus, or HPV, a common sexually-transmitted disease. Cervarix protects against HPV strains 16 and 18, which are linked to about 70% of cervical cancer cases in the U.S. Gardasil also protects against the same strains along with two others that are linked to genital warts in both men and women. There's also evidence that Cervarix protects against cancer caused by another HPV strain that is closely related to types 16 and 18.

The FDA has said that about 40 strains of HPV infect the human genital tract, so neither Cervarix nor Gardasil protects against all HPV infection.

Glaxo first sought FDA approval for Cervarix in 2007, but the FDA said it needed more information before it would consider approving the vaccine. Glaxo refiled the application for Cervarix in March.

During last month's FDA advisory committee meeting the agency raised concerns about a higher rate of miscarriages among females who received Cervarix and couldn't rule out a "small effect" on pregnancies. (Cervarix and Gardasil are not approved for use in pregnant women.)

The agency said it would require a post-marketing safety study to monitor the outcome of pregnancies in women who might receive Cervarix along with other potential safety concerns.

HPV vaccines are designed to be administered before people become sexually active. In the U.S. the CDC recommends that Gardasil be offered to 11-to-12 year old girls along with other vaccines that are routinely given to that age group. Once vaccines are approved by the FDA, they are later considered by a Centers for Disease Control and Prevention advisory panel. Private insurance companies typically wait for CDC panel endorsement of vaccines before agreeing to pay for them.

-By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294; jennifer.corbett@dowjones.com