Pfizer Inc said it has received a complete response letter from the US Food and Drug Administration (FDA) asking for additional information on the company's application for lasofoxifene. The investigational compound is currently under review for the treatment of osteoporosis in postmenopausal women at increased risk of fracture.

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

Pfizer submitted the current application for lasofoxifene on December 18, 2007. On September 8, 2008, an FDA scientific advisory panel voted 9-3 (with one abstention) that there is a population of postmenopausal women with osteoporosis in which the benefits of lasofoxifene likely outweigh the risks. FDA is not required to follow the advice of the panel.

The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency issued a positive opinion on December 18, 2008, recommending marketing authorization for lasofoxifene. The CHMP's opinion will be reviewed by the European Commission, which has authority to approve medicines for the European Union.

Lasofoxifene is a selective estrogen receptor modulator, or SERM, in the same chemical class as raloxifene.