Lasofoxifene (INN) (proposed tradename Fablyn) is a non-steroidal selective estrogen receptor modulator (SERM) which is under development by Pfizer for the prevention and treatment of osteoporosis and for the treatment of vaginal atrophy, and the result of an exclusive research collaboration with Ligand Pharmaceuticals (LGND). It also appears to have had a statistically significant effect of reducing breast cancer in women according to a study published online November 4 in The Journal of the National Cancer Institute.
In September 2005, Pfizer received a non-approvable letter from the U.S. Food and Drug Administration regarding lasofoxifene (trade name Oporia), a selective estrogen receptor modulator for the prevention of osteoporosis.
On January 2008, Ligand Pharmaceuticals, through its marketing partner, Pfizer, submitted a New Drug Application for lasofoxifene, which is expected to be marketed under the tradename Fablyn. Lasofoxifene was approved in the EU under the brand name Fablyn by the EMEA in March 2009.
In postmenopausal women with osteoporosis, lasofoxifene at a dose of 0.5 mg per day was associated with reduced risks of nonvertebral and vertebral fractures, ER-positive breast cancer, coronary heart disease, and stroke but an increased risk of venous thromboembolic events.
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