Pfizer Inc., the world's largest drugmaker, was unsuccessful in gaining U. S. sanction to sell its experimental osteoporosis drug, lasofoxifene. Osteoporosis is a disease of
bone that leads to an increased risk of fracture. It is most common in women after menopause.

Apparently, the FDA has asked Pfizer to submit some more information. The drug company did not reveal the type of information FDA was seeking. If FDA has asked for
an additional clinical study then it could cause a lengthy delay.

"Pfizer is reviewing the letter and will work with FDA to determine the appropriate next steps regarding the company's application," said Pfizer.

Pfizer had put in the current application for lasofoxifene, to be used by post-menopausal women, in December 2007.

In a meeting held on September 8, a panel of outside advisers to FDA concluded that the benefits of the drug outweigh its risks. A clinical trial held under the scrutiny of the
advisers had showed an increase in deaths, though the panel said it couldn't verify if that represented a "true increase" over patients given a placebo.