Minimized estradiol absorption with ultra-low-dose 10 microg 17beta-estradiol vaginal tablets.

OBJECTIVE: To investigate the pharmacokinetics of 10 microg and 25 microg 17beta-estradiol (E2) vaginal tablets in postmenopausal women with vaginal atrophy. METHODS: Fifty-eight women received either 10 microg or 25 microg estradiol vaginal tablets, administered once daily for 2 weeks, followed by twice-weekly dosing for 10 weeks. Blood samples were taken over 24 h at baseline (day -1) and days 1, 14, 82 and 83. Estradiol (E2), estrone (E1) and estrone sulfate (E1S) levels were quantified by gas chromatography-mass spectrometry (GCMS) and assessed by the average plasma concentration from time 0 to 24 h (C(ave)) derived from the area under the curve within 24 h (AUC((0-24))) divided by 24 h. RESULTS: Mean C(ave) values were 9.39 and 19.84 pg/ml on day 1, 6.56 and 18.29 pg/ml on day 14, and 4.64 and 9.41 pg/ml on day 83 for the 10 microg and 25 microg doses, respectively. After 12 weeks, E1 and E1S levels were slightly higher with the 25 microg dose and in the same range with the 10 microg dose, as compared to baseline. CONCLUSIONS: During 12 weeks' administration, 10 microg vaginal tablets resulted in at least 50% lower mean estradiol concentrations than with the 25 microg dose within 24 h after dosing. Administering the 25 microg dose, mean E2 levels during the first 2 weeks exceeded the published reference range for postmenopausal women using the GCMS method, while, with the 10 microg dose, mean E2 levels remained in that range from the beginning, indicating minimized estradiol absorption.

Endometrial safety of ultra-low-dose Vagifem 10 microg in postmenopausal women with vaginal atrophy.

OBJECTIVE: The objective of the study was to evaluate the endometrial safety of a 10 microg estradiol vaginal tablet in the treatment of vaginal atrophy in postmenopausal women. METHODS: A total of 336 healthy, non-hysterectomized, postmenopausal women (age 59.5 +/- 6.16 years, 9.4 +/- 5.9 years from last menses) were treated with a 10 microg estradiol vaginal tablet for 12 months (once daily for 2 weeks and then twice weekly for 50 weeks). Endometrial histology was analyzed at baseline and at the end of the trial. RESULTS: Of the 336 enrolled subjects, 292 (86.9%) completed the 52-week study. All 336 subjects received an endometrial biopsy at baseline, and 283 had biopsy results at week 52, when 258 out of the 283 biopsy samples were classified as 'atrophic' or 'inactive' endometrium. There were 21 with 'no tissue' despite a repeat biopsy attempt to obtain endometrial tissue, one had insufficient tissue with endometrial thickness >4 mm, one was 'weakly proliferative' and two revealed polyps. No cases of endometrial hyperplasia or endometrial cancer were reported. The mean endometrial thickness decreased from 2.04 mm (n = 334) from study start to 1.94 mm (n = 293) after 52 weeks, and the estradiol levels remained at the low postmenopausal level. CONCLUSIONS: After 12 months of treatment with the 10 microg estradiol vaginal tablet, there was no suggestion of endometrial stimulation and no cases of endometrial hyperplasia or cancer reported. This study provides reassuring data on the endometrial safety of treatment with the 10 microg estradiol vaginal tablet for 1 year in a large group of postmenopausal, non-hysterectomized women with vaginal atrophy.