A phase I trial to assess the pharmacology of the new oestrogen receptor antagonist fulvestrant on the endometrium in healthy postmenopausal volunteers.
Bottom Line: Fulvestrant ("Faslodex") is a new oestrogen receptor antagonist that downregulates the oestrogen receptor and has no known agonist effect.Neither the 125 mg nor 250 mg doses of fulvestrant demonstrated oestrogenic effects on the endometrium over the initial 14-day assessment period.Fulvestrant was well tolerated and reduced the incidence of ethinyloestradiol-related side effects.
Affiliation: LCG Bioscience, Bourn Hall Clinic, Bourn, Cambridge, UK.Show MeSH
Related in: MedlinePlus
Mentions: Following the 14-day treatment period 2, during which time ethinyloestradiol was administered in addition to fulvestrant (125 mg or 250 mg) and placebo, the mean endometrial thickness for the three groups was 7.70 mm for fulvestrant 125 mg plus ethinyloestradiol, 4.20 mm for fulvestrant 250 mg plus ethinyloestradiol, and 11.22 mm for placebo plus ethinyloestradiol, respectively (Table 1). There was a statistically significant difference between the fulvestrant 250 mg-treated group and the placebo-treated group for the change in mean endometrial thickness between day 1 and day 28 (P=0.0001) (Table 1). There was no statistically significant difference between the fulvestrant 125 mg group and the placebo group (P=0.0742) (Table 2Table 2Summary of plasma fulvestrant pharmacokinetic parameters). The mean endometrial thickness from pretrial to 42 days post-treatment with placebo or fulvestrant is plotted in Figure 2Figure 2
Affiliation: LCG Bioscience, Bourn Hall Clinic, Bourn, Cambridge, UK.