The situation of Merck’s papillomavirus vaccine Gardasil is uncertain after the Food and Drug Administration asked for more data before making a decision on expanding its approval to include use by older women.

 

Gardasil prevents four types of the HPV virus known to be involved in 90 percent of genital warts and 70 percent of cervical cancer. Cervical cancer is the second most common cause of cancer death in women worldwide, resulting in nearly a half-million diagnoses and 280,000 deaths each year. In 2007, there were an estimated 11,000 new cases of cervical cancer and 3,600 deaths in the US.

 

Gardasil was licensed for use in girls and women aged 9 to 26. But Merck is seeking clearance to allow the vaccine to also be used by women between 27 and 45 years old. This is the second time the FDA delays approval of the vaccine for this use. In June, the agency rejected the expanded use and identified several issues related to Merck’s application in a “complete response” letter.

 

At the time, Merck submitted 24 months worth of data from a four-year study, showing the drug is efficient for this use too. Now the FDA wants to see the final results of a four-year study, and Merck said it expects to report on the results in the fourth quarter of this year.

 

Currently Gardasil is the only cervical cancer vaccine on the market. It has racked up about $1.5 billion in sales since its June 2006 U.S. launch. Cervarix, a similar vaccine made by rival GlaxoSmithKline, is expected to hit the market by the middle of 2009.