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.[3][4]
Breast cancer
In studies of breast cancer prevention, lasofoxifene showed a 79% reduction in breast cancer incidence and an 83% reduction specific incidence of estrogen receptor-positive breast cancers, which is significantly higher than reductions found with the related SERMs tamoxifen and raloxifene.[5] In accordance, a network meta-analysis of SERMs for breast cancer prevention found the highest reduction in risk with lasofoxifene of all the drugs.[6] The reduction was even greater than that observed with aromatase inhibitors, which have generally been found to confer a greater risk reduction than SERMs.[6] It also has shown promise in ESR1 mutant patients with 'approximately 40% of patients harboring this mutation'.[7]
Pharmacology
Pharmacodynamics
Lasofoxifene selectively binds to both ERα and ERβ with high affinity.[8] Its IC50 for ERα (1.5 nM) is similar to that of estradiol (4.8 nM) and is at least 10-fold higher than those of tamoxifen and raloxifene.[3]
Effect:+ = Estrogenic / agonistic. ± = Mixed or neutral. – = Antiestrogenic / antagonistic. Note: SERMs generally increase gonadotropin levels in hypogonadal and eugonadal men as well as premenopausal women (antiestrogenic) but decrease gonadotropin levels in postmenopausal women (estrogenic). Sources: See template.
Pharmacokinetics
Lasofoxifene has greatly improved oralbioavailability relative to tamoxifen and raloxifene, and this may also be involved in its greater potency.[9]
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.
In 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.[11]
^Gennari L, Merlotti D, Martini G, Nuti R (September 2006). "Lasofoxifene: a third-generation selective estrogen receptor modulator for the prevention and treatment of osteoporosis". Expert Opinion on Investigational Drugs. 15 (9): 1091–103. doi:10.1517/13543784.15.9.1091. PMID16916275. S2CID20693299.
^ abGennari L (June 2006). "Lasofoxifene: a new type of selective estrogen receptor modulator for the treatment of osteoporosis". Drugs of Today. 42 (6): 355–67. doi:10.1358/dot.2006.42.6.973583. PMID16845439.
^Gennari L (September 2009). "Lasofoxifene, a new selective estrogen receptor modulator for the treatment of osteoporosis and vaginal atrophy". Expert Opinion on Pharmacotherapy. 10 (13): 2209–20. doi:10.1517/14656560903127241. PMID19640205. S2CID21020484.
^Lednicer D, Emmert DE, Lyster SC, Duncan GW (September 1969). "Mammalian antifertility agents. VI. A novel sequence for the preparation of 1,2-disubstituted 3,4-dihydronaphthalenes". Journal of Medicinal Chemistry. 12 (5): 881–5. doi:10.1021/jm00305a038. PMID5812203.