Lasofoxifene: Phase I data

An investigator-blinded, placebo-controlled Phase I trial in 36 healthy male volunteers showed that single doses of 1, 3, 10, 30 and 100 mg oral lasofoxifene increased testosterone levels, with the 2 highest doses increasing testosterone levels from baseline by >80%. Additionally, the 2 highest doses of lasofoxifene led to greater increases from baseline in levels of testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH) compared to placebo. Levels of the 3 hormones peaked at 3-7 days after treatment and elevations induced by higher doses of lasofoxifene were maintained through >=28 days. Data were presented at the ICE/ENDO meeting in Chicago. The trial was conducted by former partner Pfizer Inc. (NYSE:PFE, New York, N.Y.) and analyzed by Ligand. Ligand said it is looking to partner lasofoxifene for the treatment of men with low testosterone levels.

Ligand helped discover oral lasofoxifene under a 1991 collaboration with Pfizer. In 2009, the European Commission approved lasofoxifene in Europe as Fablyn to treat osteoporosis in postmenopausal women at increased risk of fracture. However, the EU approval lapsed as Pfizer did not launch Fablyn in Europe within 3 years. In 2009, Pfizer received a complete response letter from FDA for Fablyn for the indication. In 2011, rights to lasofoxifene reverted to Ligand from Pfizer (see BioCentury, Jan. 19, 2009). ...