U.S. health regulators have again withheld approval for the use of Merck & Co Inc's Gardasil cervical cancer vaccine by women aged 27 to 45, asking for longer-term clinical data, the drugmaker said on Friday according to Reuters. The U.S. Food and Drug Administration recommended Merck submit data when a 48-month study on a test group has been completed. The agency also withheld approval in June on Merck's initial application that was based on data collected through an average of 24 months. Merck shares fell nearly 3 percent in midday trading. Gardasil, one of Merck's most successful newer products, was approved in 2006 for preventing cervical cancer.
